Heating element and fluid heater and method for heating a fluid - Patents.com

Abstract

A heating element (2) for an electric fluid heater (30) comprising fluid permeable heating panels (6) having an extension along a first axis (4), the heating panels (2) extending along the first axis at an angle in the range of 45-90 degrees and arranged adjacent to one another along the first axis with a space between adjacent heating panels. Each heating panel comprises a three-dimensional structure, the three-dimensional structure comprising multiple members (45) of at least one electrically conductive material. The heating element has a three-dimensional shape bounded in part by a first side (10) and an opposing second side (12). The heating panels are electrically connected in series via electrical connectors (14) arranged on the first and second sides. The three-dimensional structure comprises at least three members arranged one after the other along the first axis and connected to one another at nodes (47).

Description

[Technical field]

[0001] The present invention relates to a heating element for an electric fluid heater and to an electric fluid heater. The present invention also relates to a method for heating a fluid in an electric fluid heater. [Background technology]

[0002] An electric heater may include one or more electrical resistive heating elements arranged to heat a fluid passing through the heater. Conventionally, each wire, strip, or tube used as a heating element has a heating effect achieved by the passage of an electric current through the relatively thin wire, strip, or tube.

[0003] One type of electric heater comprises one or more electric heating channels forming an element for heating a fluid. For example, WO2009 / 071590, EP2784049 and US2007 / 0189741 disclose such heating systems with ceramic electric resistance heating elements forming one or more channels through which a fluid passes to become a heated stream. A current source is directly connected to the associated electric resistance heating element.

[0004] In EP2784049 the heating system comprises two or more channels forming an element electrically connected in parallel.Similarly, in the heating system of US2007 / 0189741, two or more channels forming an element are electrically connected in parallel while some of the channels forming the elements are also connected in series.

[0005] Regardless of the electrical connections of the channels forming the heating element in the systems of WO2009 / 071590, EP2784049 and US2007 / 0189741, the individual channels forming the heating element extend along the flow path of the fluid to be heated, i.e. the individual channels of the heating element through which the fluid passes to become the heated stream are arranged in parallel along the entire length of the fluid through which it is heated.

[0006] No. 3,244,860 discloses a heater for gases comprising a metal mesh electrical resistance heating element arranged within a casing. A number of individual mesh strips arranged in concentric circles of hexagonal cross section form the heating element. The individual mesh strips are electrically connected in parallel. Gas flows radially inward through the casing and through the mesh strips, thereby becoming heated.

[0007] In contrast to the heating systems of WO 2009 / 071590, EP 2784049 and US 2007 / 0189741, in the system of US 3,244,860 the mesh strips are arranged so that gas flows sequentially, i.e. in series, through each mesh strip.

[0008] WO2021 / 083947 discloses a heating element with a body having a three-dimensional matrix with an open structure including openings or internal voids, cavities and / or pores extending throughout the body. The three-dimensional matrix is ​​provided as a lattice with repeating unit cells extending in three directions. The electrical connections of the body are not discussed in detail.

[0009] DE102019113518 discloses a fluid heater with a heating element comprising fibers formed from insulated wire. Summary of the Invention

[0010] There remains a need for an effective and efficient electric heater for heating fluids.

[0011] It would therefore be advantageous to achieve an efficient electric fluid heater. In particular, it would be desirable to enable a compact electric heater with a simple structure. To better address one or more of these considerations, at least one of a heating element for an electric fluid heater, an electric fluid heater, and a method for heating a fluid in an electric fluid heater is provided as defined in the independent claims.

[0012] According to one aspect, a heating element for an electric fluid heater is provided, the heating element comprising fluid permeable heating panels having an extension along a first axis, the heating panels extending at an angle in the range of 45-90 degrees relative to the first axis and arranged adjacent to one another along the first axis with a space between adjacent heating panels. Each heating panel comprises a three-dimensional structure, the three-dimensional structure comprising multiple members of at least one electrically conductive material. The heating element has a three-dimensional shape delimited in part by a first side and an opposing second side, the first and second sides extending substantially parallel to the first axis, and the heating panels extending between the first and second sides. The heating panels are electrically connected in series via electrical connectors arranged at the first and second sides. The three-dimensional structure comprises at least three members arranged one after the other along the first axis and connected to one another at nodes.

[0013] Because the heating panels are arranged adjacent to one another along a first axis with spaces between adjacent heating panels, because each heating panel comprises a three-dimensional structure comprising multiple members of at least one electrically conductive material, because the heating panels are electrically connected in series via electrical connectors arranged on first and second sides, and because the three-dimensional structure comprises at least three members arranged one after the other along the first axis and connected to one another at nodes, the heating element has a compact structure that provides high energy transfer in a form that is easily incorporated into an electric fluid heater, and thus the heating element provides an efficient electric fluid heater.

[0014] More specifically, the heating panels of a heating element are arranged electrically in series such that the length of the conductive path through the heating element is longer than the length of the heating element along the first axis. When designing a particular heating element of the type discussed herein, by selecting the number of heating panels within the heating element and thus the length of the conductive path in particular, the electrical resistance, and therefore the energy transfer, may be flexibly adjusted within a given length of the heating element.

[0015] According to a further aspect, an electric fluid heater is provided that includes a housing having a fluid inlet and a fluid outlet. A fluid flow path for heating a fluid is defined within the housing. At least one heating element according to any one of the aspects and / or embodiments discussed herein is arranged with a first axis of the heating element extending along at least a portion of the fluid flow path.

[0016] Since the electric fluid heater comprises at least one heating element according to any one of the aspects and / or embodiments discussed herein, a compact and efficient electric fluid heater is provided.

[0017] According to a further aspect, there is provided a method for heating a fluid in an electric fluid heater according to any one of the aspects and / or embodiments discussed herein. The method includes: providing a fluid to a fluid inlet; providing an electrical current to at least one heating element to heat the heating panel; conducting a fluid along a fluid flow path through the heating panel to a fluid outlet; directing the fluid through a fluid outlet; Includes.

[0018] The method is carried out utilizing an electric fluid heater according to any one of the aspects and / or embodiments discussed herein, thus providing an efficient method for heating a fluid.

[0019] As mentioned above, the heating element has a three-dimensional shape bounded in part by a first side and an opposing second side. Thus, the heating element may generally have a substantially cylindrical, cubic, rectangular, prismatic, or parallelepiped shape.

[0020] The first and second sides, as well as further sides of the heating element, form sides of the three-dimensional shape, but the heating element may open more or less from these sides. In other words, these sides may not necessarily be formed by continuous wall elements. Because the fluid flow path for heating the fluid is defined within the housing of the electric fluid heater in which the heating element is arranged, a continuous wall element may not therefore be required within the heating element.

[0021] It is the first and second sides extending substantially parallel to the first axis that give the heating element a three-dimensional shape that may be easily arranged within the housing of an electric fluid heater, which may also contribute to a substantially constant cross-sectional area perpendicular to the first axis through the entire heating element and along the fluid flow path.

[0022] More specifically, as used herein, a heating element comprises heating panels electrically connected to one another in series from a first end of the heating element to an opposing second end of the heating element, the first and second ends being viewed along a first axis.

[0023] The heating panels of a heating element may be arranged along one or more rows in parallel on the first axis. There is a gap between adjacent heating panels within a row of heating panels and between adjacent heating panels of adjacent rows of heating panels. The heating panels of each row of heating panels extend between first and second sides of the heating element to which the heating panels are electrically connected via an electrical connector.

[0024] The spacing between adjacent heating panels is defined by an air gap between the adjacent heating panels or a non-conductive fluid-permeable material arranged between the adjacent heating panels. Specifically, electrical current cannot flow through the spacing between adjacent heating panels. Electrical current can only flow between two adjacent heating panels on the first or second side of the heating element through one of the electrical connectors.

[0025] As described above, the heating panels are electrically connected in series via electrical connectors arranged on the first and second sides. Such electrical connections via electrical connectors may be between adjacent heating panels within a row of heating panels and / or adjacent heating panels of adjacent rows of heating panels, and regardless of the number of rows of heating panels within a heating element, the heating panels of a heating element are electrically connected in series from a first end of the heating element to a second end of the heating element.

[0026] Thus, a conductive path is formed through the heating panels of the heating element. The conductive path meanders in one or more directions relative to the first axis. If the heating element comprises only one row of heating panels, the conductive path meanders in only one direction relative to the first axis. If the heating element comprises two or more rows of heating panels, the conductive path meanders in two directions relative to the first axis.

[0027] According to an embodiment, a conductive path is provided through the heating element by the heating panel and the electrical connector, the heating element having a length along a first axis, and the conductive path may be longer than the length along the first axis.

[0028] When a heating element comprises only one row of heating panels, adjacent heating panels in that row are electrically connected in series with each other.

[0029] According to an embodiment, when a heating element comprises only two rows of heating panels, i.e., a first row of heating panels and a second row of heating panels, the heating panels in the first and second rows are electrically connected in series, alternating between connecting adjacent heating panels in the first row and in the second row, and alternating between connecting adjacent heating panels in the first and second rows, such that all heating panels in the first and second rows are electrically connected in series via a conductive path that meanders from a first end of the heating element to an opposite second end of the heating element.

[0030] According to an embodiment, when the heating element comprises three or more rows of heating panels, i.e. a first outermost row, a second outermost row, and at least one intermediate row between the first and second outermost rows, the heating panels of the three or more rows are electrically connected in series by connecting adjacent heating panels in adjacent rows. The heating panels of the first outermost row are electrically connected in series to the heating panels of the second outermost row through adjacent heating panels of at least one intermediate row. Thus, a series-connected line of heating panels is formed that extends across at least three rows of heating panels and across the first axis. These series-connected lines of heating panels are alternately connected through adjacent heating panels in the first outermost row and adjacent heating panels in the second outermost row, such that all heating panels of the at least three rows are electrically connected in series through a conductive path that meanders from the first end to the second end of the heating element.

[0031] According to an embodiment, the heating panels may be electrically connected in series only via the electrical connectors arranged on the first and second sides.

[0032] According to some embodiments, the length of the heating element along the first axis may be greater than the maximum width of the heating element between the first and second sides.

[0033] The three-dimensional structure with multiple members provides fluid permeability for each heating panel, i.e., multiple voids exist between the multiple members through which fluid can pass and permeate the heating panel.

[0034] The multiple members are connected to each other at multiple nodes. Groups of members comprising at least two members of the multiple members are connected to each other at each node of the multiple nodes.

[0035] The nodes form conductive connections between the members.

[0036] Thus, current will flow through one member and through the associated node to a further connected member.

[0037] During use of the heating elements, within each heating panel, electrical current flows between the first and second sides of the heating elements through a number of members electrically connected in series and parallel.

[0038] The 3D structure is freestanding, i.e. the members are stiff or rigid and the connections between the members at the nodes are rigid connections, i.e. the connections / nodes are capable of transmitting torque between the connected members, in other words the connections of the members at the nodes are not journalled or rotatable.

[0039] A freestanding structure is one that does not require additional elements or devices, such as a frame, to maintain its structure. In other words, the positions of the members and the angles between the members in the three-dimensional structure are maintained, again without a frame. That is, in the present case, the members and nodes of the three-dimensional structure are sufficient for the three-dimensional structure to maintain its structure.

[0040] The heating panels may have any suitable shape, so long as they can be arranged adjacent to one another along a first axis with spacing between adjacent heating panels. For example, when viewed in a view along the first axis, the heating panels may have a circular, elliptical, square, rectangular, or hexagonal shape. When viewed in a side view perpendicular to the first axis, each heating panel may have, for example, a rectangular, parallelogram, S-, C-, V-, or diamond shape.

[0041] Each heating panel may have an extension perpendicular to the first axis, for example between the first and second sides, that is longer than the extension of the heating panel along the first axis.

[0042] Along the first axis, one or more of the heating panels may be different from one another.

[0043] The thickness of each heating panel juxtaposed to the first axis may vary among different portions of one or more of the heating panels.

[0044] In a panel having a rectangular or parallelepiped shape, seen in a view perpendicular to the first axis, the angle at which the heating panel extends to the first axis is quite clear.

[0045] For heating panels having curved or angled shapes and / or different thicknesses when viewed in a view perpendicular to the first axis, the angle at which the heating panel extends relative to the first axis is the angle of the centerline of the heating panel, i.e., the centerline as viewed in a view perpendicular to the first axis. Depending on the shape of the heating panel, the centerline may be a straight line or may vary in direction.

[0046] According to an embodiment, the heating element may comprise at least two heating panels. In this way, at least two heating panels may be provided which are to be electrically connected in series.

[0047] The heating element may comprise more than 10 heating panels, or more than 50 heating panels, or more than 100 heating panels.

[0048] The number of heating panels may depend on, among other things, the thickness of the individual heating panels, the total energy transfer to be transmitted by the heating elements, the voltage to be connected to the heating elements, the temperature rise to be achieved within the heating elements, the fluid flow through the heating elements, the desired electrical resistance, and the desired heat transfer performance.

[0049] The heating panels are electrically connected in series via electrical connectors arranged on the first and second sides.

[0050] By arranged on a side it is meant that such electrical connectors may be provided between laterally adjacent heating panels and / or that such electrical connectors may be provided extending along at least a portion of laterally adjacent heating panels.

[0051] Electrically connecting heating panels in series provides flexibility in achieving a desired electrical resistance value within the heating element. Connecting fewer or more heating panels in series provides lower or higher resistance values. The number of panels, and therefore the total resistance value of the heating element, can be selected such that the heating element can be heated to a desired lower or higher temperature, for example, by passing an electrical current through the series-connected heating panels. Furthermore, by connecting a suitable number of heating panels in series, design power ratings, power supply capabilities, specific surface loads, etc. can be met.

[0052] According to embodiments, the heating element may comprise at least two rows of heating panels arranged adjacent to one another along the first axis.

[0053] According to an embodiment, each of the at least two rows of heating panels may include at least two heating panels.

[0054] According to some embodiments, each of the at least two rows of heating panels may include between 4 and 200 heating panels or between 4 and 500 heating panels.

[0055] According to an embodiment, the heating panels of at least two rows of heating panels will be electrically connected in series along a conductive path from a first end of the heating element as viewed along a first axis to an opposite second end of the heating element via electrical connectors arranged alternately on the first and second sides. Some of the electrical connectors may extend between adjacent heating panels within a row of heating panels, and some of the electrical connectors may extend between heating panels of adjacent rows of heating panels. In this way, the heating panels arranged in at least two rows can be electrically connected to each other from the first end to the second end of the heating element. The conductive path thus formed is serpentine through the heating elements from the first end to the second end.

[0056] A particular length of heating element may be required to provide a desired temperature rise of a fluid passing along a first axis through an electrically heated heating element to a particular temperature. The length of the heating element is influenced by the number of heating panels, the distance between the heating panels, and the length of each heating panel along the first axis. Thus, providing a heating element of a suitable length may also influence the number of heating panels in the heating element.

[0057] According to some embodiments, all heating panels of a heating element are electrically connected in series, for example along a first axis, adjacent heating panels are alternately electrically connected at first and second sides via electrical connectors.

[0058] The electrical resistance of a heating element can be affected by the number of heating panels electrically connected in series. One way to increase the electrical resistance for a given length of a heating element along a first axis can be to arrange two or more rows of heating panels in parallel on the first axis and electrically connect all heating panels of the two or more rows of heating panels in series to form a conductive path from a first end to a second end of the heating element. Thus, a heating element can be devised to be electrically heated to a desired temperature by arranging heating panels connected in series in several rows.

[0059] According to some embodiments, within a heating element, the heating panels may form two or more sets of heating panels. For example, the heating panels of such two or more sets of heating panels may be interlaced along the first axis. Within each set of heating panels, the heating panels may be connected in series. Two or more such sets of heating panels may be connected in series or in parallel.

[0060] The heating element may include two terminals for connecting power to the heating element: one terminal may be provided at an opposite end of the heating element, for example arranged at the outermost heating panel of the heating element.

[0061] In an embodiment, the heating element may comprise two or more sets of heating panels connected in series, with each set of heating panels comprising two terminals for connecting power to a respective set of heating panels.

[0062] As mentioned above, the three-dimensional structure of the heating panel comprises at least three members arranged one after the other along a first axis and connected to each other at nodes. This means that along the first axis, each heating panel has a length of at least three members. The three members may be arranged at an angle to the first axis. Thus, the length of the heating panel along the first axis may be less than the total length of the three members.

[0063] Within the three-dimensional structure, members are connected to one another at nodes, which may be defined by forming connection points between at least three members and / or connection points between two members with an abrupt change of direction between the members.

[0064] The members of a three-dimensional structure may be arranged with greater or lesser regularity within the structure. In a regular arrangement of members within a three-dimensional structure, the arrangement of members is repeated at regular intervals.

[0065] The three-dimensional structure may form a lattice body with a regularly repeating structure of members and nodes, which forms an open structure, i.e., a fluid-permeable structure.

[0066] A three-dimensional structure can be advantageous because it can be formed into any shape and configuration. This can be achieved because it is lightweight and strong and can be manufactured by techniques such as additive manufacturing. The open structure of the three-dimensional structure allows the flow of the fluid to be heated to pass through the heating element.

[0067] An additional advantage of three-dimensional structures may be the availability and freedom of options to design the fluid flow path / s through the structure. For example, a relatively dense structure may provide a higher fluid flow resistance than a less dense structure.

[0068] According to an embodiment, the three-dimensional structure comprises gaps between the members, the gaps allowing fluid to pass through the heating panel, and the volume ratio of the gaps to the members of the three-dimensional structure may be in the range of 1:1 to 10000:2. In this way, efficient energy transfer may be achieved by the heating element.

[0069] According to an embodiment, the members are connected at the nodes to form a number of unit cells. In this manner, three-dimensional structures can be provided in an efficient and repeatable manner, suitable for production in, for example, additive manufacturing processes.

[0070] Therefore, the smallest repeating structure of a three-dimensional structure may be a unit cell.

[0071] In the context of a unit cell, members may be referred to as struts. In this specification, the term members will be used with respect to the struts of a unit cell.

[0072] Thus, within a three-dimensional structure, a first unit cell may share members and nodes with an adjacent second unit cell, i.e., the members and nodes that form the boundary between the first and second unit cells may be understood to form part of each of the first and second unit cells.

[0073] In a three-dimensional structure, the regularly repeating structures may extend in three directions, namely, a first, a second, and a third direction. One of these directions may coincide with the first axis. Alternatively, none of these directions coincide with the first axis.

[0074] In the case of a three-dimensional structure formed by unit cells, the unit cells are arranged adjacent to each other in three directions. The three directions may extend at the same angle relative to each other. That is, the angle between the first and second directions may be equal to the angle between the second and third directions and the angle between the first and third directions. For example, the angles between these directions may be 90 degrees or 60 degrees.

[0075] The three-dimensional structure formed by the unit cells can advantageously withstand the thermal, physical, and mechanical demands within the heating element.

[0076] According to an embodiment, the first heating panel comprises: 3D structure, The cross-sectional area, thickness or width of the member, The size, shape, or number of voids in the heating panel; The heating panel may differ from the second heating panel by only one or a combination of: the length along the first axis of the heating panel, or the length along the first axis of the heating panel. In this manner, different attributes may be imparted to the first and second heating panels.

[0077] Thus, for example, the electrical resistance of the first and second heating panels may be different, the flow resistance of the first and second heating panels may be different, etc. Such differences may be desired depending on the location of the associated first and second heating panels within the heating element.

[0078] According to the present disclosure, any material that can be used as the conductive material is suitable. Thus, according to an embodiment, the at least one conductive material is selected from the group of iron chromium aluminum (FeCrAl) alloys, nickel chromium alloys, copper nickel-based alloys, iron nickel chromium alloys, nickel iron chromium aluminum alloys, ceramic materials, intermetallic materials, tungsten-based compounds, and molybdenum-based compounds, or combinations thereof. According to an embodiment, the material may be selected from graphitic steel or stainless steel. According to an embodiment, the tungsten-based compounds and the molybdenum-based compounds may be selected from compounds including tungsten / molybdenum and silica.

[0079] According to embodiments, each of the heating panels may be the result of an additive manufacturing process. In this manner, the heating panels may be manufactured in an efficient manner with one or more of the materials discussed herein.

[0080] Specifically, using additive manufacturing, three-dimensional structures can be precisely manufactured at a small scale, i.e., at the component level. Precisely manufactured heating panels for specific energy transfer ranges can thus be provided.

[0081] For example, additive manufacturing allows the production of components having a thickness as small as 0.1 mm and a length as small as 1 mm. Typically, the thickness may be in the range of 0.2-1 mm. However, the thickness range may be 0.1-10 mm or more. Typically, the length of the components may be in the range of 0.5-5 mm. However, the length range may be 0.1-50 mm.

[0082] Moreover, additive manufacturing processes provide an efficient way of producing the three-dimensional structure of a heating panel as a regularly repeating structure of multiple members. For example, in embodiments where the members form part of a unit cell, the members and nodes can be efficiently produced.

[0083] Lightweight and strong components can be manufactured by additive manufacturing. Providing flexibility in producing advanced component and node structures, as well as fluid-permeable three-dimensional structures, can be achieved with additive manufacturing processes.

[0084] According to an embodiment, the electrical connector may be the result of an additive manufacturing process. In this way, the heating panel and the electrical connector of the heating element may be manufactured in one manufacturing process.

[0085] That is, the main portions of the heating element, the heat producing heating panels, and the electrical connectors that provide the serial connection between the heating panels can be easily and efficiently produced as a single unit by additive manufacturing processes, and such a unit may require only a few further manufacturing steps before it is ready to be arranged into an electric fluid heater.

[0086] The electrical connector may be of the same or similar three dimensional structure as the heating panel. Alternatively, the electrical connector may be of a solid material.

[0087] The electrical connector may be of the same conductive material as the heating panel, or alternatively, the electrical connector may be of a different conductive material than the heating panel.

[0088] According to the embodiment of the heating element comprising terminals for connecting power to a heating panel, those terminals may also be the result of an additive manufacturing process.

[0089] In such an embodiment, the heating element, including the heating panel, electrical connectors, and terminals that are manufactured in an additive manufacturing process, may not require any further manufacturing steps or may only require few further manufacturing steps before it is ready to be arranged into the electric fluid heater.

[0090] According to an embodiment, the heating element may comprise non-conductive spacer elements arranged between adjacent heating panels of the row of heating panels on the first and second sides. In this way, it may be ensured that individual heating panels are not shorted within the heating element. Also, the provision of spacer elements may improve the stability of the heating element.

[0091] According to an embodiment, the heating element comprises at least two rows of heating panels, and at least one non-conductive additional spacer element may be arranged between adjacent heating panels of adjacent rows of heating panels. In this way, it can be ensured that individual heating panels are not short-circuited between the rows of heating panels within the heating element. Also, the provision of the additional spacer element may improve the stability of the heating element.

[0092] During use of the electric fluid heater, the fluid to be heated passes through at least one heating element and is heated within the heating element, i.e., the fluid to be heated enters the electric fluid heater, passes through the electric fluid heater, and leaves the electric fluid heater at an elevated temperature, for example, this may be done according to the methods discussed herein.

[0093] Electric fluid heaters may be utilized to heat a fluid stream in any industrial or domestic device or process. The fluid may be a gas, such as air. Thus, the electric fluid heater may be for heating a gas stream. The fluid may be a liquid. Thus, the electric fluid heater may be for heating a liquid stream or for heating steam.

[0094] The heating element may be arranged within the housing of the electric fluid heater such that the heating element fills the fluid flow path in at least a direction perpendicular to the first axis, such that the entire fluid flow may pass through the heating element along the first axis.

[0095] An electric fluid heater may include two or more heating elements arranged similarly or differently with the first axes of each of the electric fluid heaters arranged along the flow path. The heating elements may differ, for example, in the temperature to which they are electrically heated, the conductive material of the heating panels, the number of heating panels, the length of the heating elements along their respective first axes, the three-dimensional configuration of the heating panels, etc.

[0096] Two or more heating elements may be arranged one after the other along the flow path, and / or two or more heating elements may be arranged in parallel along the flow path.

[0097] Within a fluid heater, two or more heating elements may be electrically connected in series and / or in parallel.

[0098] Further features and advantages of the present invention will become apparent from a review of the appended claims and the following detailed description.

[0099] Various aspects and / or embodiments of the present invention, including particular features and advantages of the present invention, will be readily understood from the exemplary embodiments discussed in the following detailed description and accompanying drawings. [Brief description of the drawings]

[0100] [Figure 1a-1c] FIG. 2 illustrates a heating element according to an embodiment. [Figures 2a)-2c)] FIG. 2 illustrates a portion of a three-dimensional structure according to an embodiment. [Figure 3a-3c] FIG. 1 illustrates an electric fluid heater according to an embodiment. [Figure 4a-4b] FIG. 1 illustrates an electric fluid heater according to an embodiment. [Diagram 5] FIG. 1 illustrates a method for heating a fluid. [Figure 6a-6d] FIG. 1 illustrates four heating elements according to an embodiment. [Figure 7a-7b] FIG. 2 illustrates a heating element according to an embodiment. [Figure 8a-8d] FIG. 1 illustrates two heating elements according to an embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0101] Aspects and / or embodiments of the present invention are now more fully described. Like numbers refer to like elements throughout the specification. Well-known functions or constructions are not always described in detail for brevity and / or clarity.

[0102] Figures 1a-c show a heating element 2 according to an embodiment. In Figure 1a, the heating element 2 is shown in an end view, i.e., a view showing the inlet or outlet end of the heating element 2. In Figure 1b, the heating element 2 is shown in a side view, i.e., a view along the fluid flow path through the heating element 2. Figure 1c shows a portion of the three-dimensional structure of the heating element 2.

[0103] The heating element 2 is configured for use in an electric fluid heater, in which, when arranged, a fluid flow path is defined such that the fluid to be heated flows through the heating element 2. See, for example, Figures 3a-3c, and see further below.

[0104] The heating element 2 has an extension along a first axis 4, shown by a thin dashed line in Figure 1c. Viewed along the first axis 4, the heating element 2 has a first end 5 and an opposite second end 7. Fluid to be heated within the heating element 2 flows through the heating element 2 parallel to the first axis 4 along a fluid flow path.

[0105] The heating element 2 comprises a number of fluid-permeable heating panels 6. The heating panels 6 are arranged adjacent to one another along a first axis 4 with a spacing 8 between adjacent heating panels 6. The heating panels 6 are arranged along a row 9.

[0106] Each of the heating panels 6 extends at an angle α in the range of 45 to 90 degrees relative to the first axis 4. In the embodiment shown, the heating panels 6 extend perpendicular to the first axis 4, i.e. the angle α is 90 degrees.

[0107] According to some embodiments, as in the embodiment shown, the heating panels 6 may be arranged extending parallel to one another.

[0108] The heating element 2 has a three-dimensional shape bounded in part by a first side 10 and an opposing second side 12. The first and second sides 10, 12 extend substantially parallel to the first axis 4. A heating panel 6 of the heating element 2 extends between the first and second sides 10, 12. That is, the heating panel 6 extends across the first axis 4.

[0109] In the embodiment shown, the heating element 2 has a generally cuboid shape. The three-dimensional shape of the heating element 2 is therefore delimited by further opposite side faces 11, 13. The further side faces 11, 13 also extend substantially parallel to the first axis 4.

[0110] A side surface extending substantially parallel to the first axis may mean that the associated side surface extends at an angle in the range of 0 to 5 degrees relative to the first axis 4.

[0111] The heating panels 6 are made of at least one electrically conductive material. The heating panels 6 are electrically connected in series via electrical connectors 14. The electrical connectors 14 are arranged on the first and second sides 10,12.

[0112] Between two adjacent heating panels 6, electrical current can only flow through the electrical connectors 14 arranged between the panels. No electrical current can flow through the gap 8 between the two adjacent heating panels 6.

[0113] More specifically, the electrical connectors 14 are arranged in an alternating fashion on the first and second sides 10, 12. In this manner, electrical current through the heating element 2 flows in series through the individual heating panels 6 between the first and second ends 5, 7 of the heating element 2.

[0114] According to some embodiments, the heating panels 6 are electrically connected in series only via the electrical connectors 14 arranged on the first and second sides 10,12.

[0115] An electrically conductive path P, shown by a thick dashed line in FIG. 1c, is provided through the heating element 2 by the heating panel 6 and the electrical connector 14. The heating element 2 also has a length L along the first axis 4. Because the heating panel 6 is electrically connected in series via the electrical connectors 14 arranged on the first and second sides 10, 12, the electrically conductive path P through the heating element 2 is longer than the length L of the heating element 2 along the first axis 4. As discussed herein, the electrically conductive path P meanders through the heating element 2.

[0116] According to some embodiments, the heating element 2 may include non-conductive spacer elements 16 arranged between adjacent heating panels 6 on the first and second sides 10, 12. Thus, the heating panels 6 are prevented from getting too close to each other on sides 10, 11, 12, 13 of the heating panels 6 where the heating panels 6 are not connected to each other via the electrical connectors 14. Because the spacer elements 16 are arranged on the first and second sides 10, 12, the spacer elements 16 do not impede the flow of the fluid to be heated through the heating element 2, at least not to any significant extent.

[0117] According to some embodiments, along the first side 10, one of the electrical connectors 14 may extend between two adjacent heating panels 6 to form a pair 18 of heating panels 6, and one of the spacer elements 16 may be arranged between the pair 18 of heating panels 6 and a further adjacent heating panel 6'. Along the second side 12, one of the spacer elements 16 may be arranged between two heating panels 6 of the pair 18 of heating panels 6, and one of the electrical connectors 18 may extend between one of the heating panels 6 of the pair 18 of heating panels 6 and a further adjacent heating panel 6'.

[0118] In the embodiment shown, the heating element 2 comprises two terminals 20, indicated by dash-dotted lines, for connecting power to the heating element 2. One terminal 20 is provided at each opposite end of the heating element 2, as viewed along the first axis 4.

[0119] Each of the heating panels 6 comprises a three-dimensional structure. The three-dimensional structure comprises multiple members 45 of at least one electrically conductive material.

[0120] The three-dimensional structure with multiple members 45 provides fluid permeability for each heating panel 6. In the three-dimensional structure, multiple voids exist between the multiple members 45 through which void fluid can permeate the heating panel 6.

[0121] The three-dimensional structure comprises at least three members 45 arranged one after the other along a first axis 4 and connected to each other at nodes 47, see FIG. 1c.

[0122] In the embodiment shown in Figures 1a-1c, members 45 and nodes 47 are arranged to form a number of unit cells having an octahedral shape.

[0123] For further discussion of the details of three-dimensional structures and alternative three-dimensional structures, see below with reference to Figures 2a)-2c).

[0124] The at least one conductive material used is any material capable of conducting electricity.Thus, the material is selected from the group of iron-chromium-aluminum alloys, nickel-chromium alloys, copper-nickel based alloys, iron-nickel-chromium alloys, nickel-iron-chromium-aluminum alloys, ceramic materials, intermetallic materials, tungsten-based compounds, and molybdenum-based compounds, or combinations thereof.

[0125] The three dimensional structure includes voids between the members, which allow fluid to pass through the heating panel 6. The volume ratio of voids to members of the three dimensional structure may be in the range of 1:1 to 10000:2.

[0126] According to some embodiments, each of the heating panels 6 may be the result of an additive manufacturing process. Also, one or more of the electrical connectors 14 and / or terminals 20 may be the result of an additive manufacturing process.

[0127] According to an embodiment, the thickness of member 45 may be in the range of 0.05 to 10 mm, or in the range of 0.1 to 4 mm, or in the range of 0.2 to 1 mm, and the length of member 45 may be in the range of 0.1 to 50 mm, or in the range of 0.2 to 15 mm, or in the range of 0.5 to 5 mm.

[0128] The thickness of member 45 extends perpendicular to the length of member 45. When member 45 has a different thickness, the thickness ranges discussed above relate to the average thickness of member 45.

[0129] In the embodiment shown, the heating element 2 comprises five heating panels 6. According to alternative embodiments, the heating element 2 may comprise more or less than five heating panels 6.

[0130] According to some embodiments, the first heating panel 6′ comprises: 3D structure, The cross-sectional area, thickness, or width of the member; The size, shape, or number of voids within the heating panel 6', 6"; Length of panels 6', 6" along first axis 4 may differ from the second heating panel 6'' in any one or combination of these.

[0131] Thus, at different locations within the heating element 2, different attributes may be provided by the first and second heating panels 6', 6''.

[0132] According to an embodiment, the heating panel may be designed and arranged for an energy transfer of up to 5 kW / cm3. In this way, a compact heating element providing high and therefore efficient energy transfer may be provided.

[0133] According to embodiments, the heating panel may be configured to be electrically heated to a temperature of up to 1450 degrees Celsius, up to a temperature of up to 1900 degrees Celsius, or up to a temperature in the range of 1700-1900 degrees Celsius, or up to a temperature in the range of 1600-2000 degrees Celsius. In this manner, the fluid to be heated may be heated to high temperatures that may be utilized in industrial processes.

[0134] Such a temperature or temperature range may be applied within the heater, with the conductive material being selected from any of the alloys mentioned above.

[0135] According to some embodiments, such temperatures up to 1450 degrees Celsius may be applied in the heating element 2, the conductive material being an FeCrAl (iron chromium aluminium) alloy or a nickel-based alloy.

[0136] According to some embodiments, such temperatures up to 1900 degrees Celsius or a temperature range of 1700-1900 degrees Celsius may be applied within the heating element, and the conductive material is a molybdenum-based alloy.

[0137] According to some embodiments, such temperatures up to 2000 degrees Celsius or a temperature range of 1600-2000 degrees Celsius may be applied within the heating element, and the conductive material is a silicon-based alloy.

[0138] Figures 2a) to 2c) show a portion of a three-dimensional structure according to an embodiment. Such a three-dimensional structure may be a three-dimensional structure similar to that discussed above with reference to Figures 1a to 1c. Therefore, in the following, reference is also made to Figures 1a to 1c.

[0139] As described above, each of the heating panels of the heating element comprises a three-dimensional structure that comprises multiple members 45 of at least one electrically conductive material. Between the multiple members 45 there are multiple voids.

[0140] According to these embodiments, the three-dimensional structure comprises a regularly repeating structure of members 45 and nodes 47 .

[0141] Similarly, with respect to the three-dimensional structure discussed above with reference to Figures 1a-1c, when arranged within the heating panel 6 of the heating element 2, the three-dimensional structure comprises at least three members 45 arranged one after the other along the first axis 4 and connected to each other at nodes 47.

[0142] 2a) and 2b) each show one so-called unit cell 25. The unit cell 25 comprises members 45 connected at nodes 47. A large number of unit cells 25 are arranged in the heating panel 6 of the heating element 2, i.e. the three-dimensional structure of members 45 are connected at nodes 47 to form a large number of unit cells 25.

[0143] 2a) and 2b) show an example of a minimal repeating structure of a three-dimensional structure, a unit cell 25. Each unit cell 25 is formed from stiff or rigid members 45 connected at nodes 47. The connections between members 45 at nodes 47 are rigid. Thus, a unit cell 25 is a free-standing structure, and a structure comprising several unit cells 25 is also a free-standing structure.

[0144] There is a gap 27 between the member 45 and the node 47 .

[0145] Thus, the regularly repeating structure of members 45 and nodes 47 with voids between them is a fluid permeable structure. As a fluid flow passes through the fluid permeable structure, the fluid flow is heated by the electrically heated members 45 and nodes 47.

[0146] Such a unit cell 25 may be repeated throughout at least a major portion of the three-dimensional structure.

[0147] Within different heating panels 6 of the heating element 2, the three-dimensional structure may comprise different unit cell geometries to form heating panels 6 that differ in size, shape, and plurality of members 45 and / or voids 27.

[0148] The exemplary unit cell configuration in FIG. 2a) is a face-centered cubic (fcc) unit cell 25. The exemplary unit cell configuration in FIG. 2b) is a body-centered cubic (bcc) unit cell 25.

[0149] Thus, the feature that the three-dimensional structure of each heating panel 6 comprises at least three members 45 arranged one after the other along the first axis 4 and connected to each other at nodes 47 means that in embodiments where the three-dimensional structure comprises an fcc unit cell 25 as shown in FIG. 2 a) or a bcc unit cell 25 as shown in FIG. 2 b), the three-dimensional structure comprises at least one and a half unit cells 25 arranged along the first axis 4.

[0150] In a three-dimensional structure with a simple cubic unit cell, i.e., without any central node, the feature that the three-dimensional structure comprises at least three members 45 arranged one after the other along the first axis 4 and connected to each other at nodes 47 means that the three-dimensional structure comprises at least three unit cells 25 arranged along the first axis 4.

[0151] The unit cell 25 may have a diameter or width of at least 0.1 mm. The member 45 may have a diameter of at least 0.05 mm. According to some embodiments, the member 45 may have a diameter or mean diameter greater than 0.05 mm, such as 0.05 to 4 mm. The diameter or mean diameter of the member 45 is measured perpendicular to the longitudinal extension of the member 45. If the member 45 does not have a circular cross-section and / or the diameter varies along the extension of the member 45, the mean diameter is the average diameter.

[0152] Figure 2c) shows some unit cells 72 of a portion of the three-dimensional structure of the heating panel 6. The three-dimensional structure is free-standing.

[0153] Each unit cell 72 is shown generally as a cube and may be one of the types discussed with respect to Figures 2a) and 2b), however, the unit cells 72 are not limited to the embodiment shown and may have any suitable internal structural members and any other suitable external shape, such as, for example, a tetrahedral or octahedral shape.

[0154] The unit cells 72 are arranged next to each other in three dimensions. Members and nodes of adjacent unit cells 72 are shared to form a regularly repeating three-dimensional structure within the heating panel 6. More specifically, at the corners of each unit cell 72, members from adjacent unit cells 72 are connected to each other, thereby forming nodes. Except at the exterior surface of the heating panel 6, each unit cell 72 is surrounded by other unit cells 72, such that the unit cells are arranged next to each other in three dimensions. For example, the heating panel 6 comprises at least two unit cells 72, 72' arranged next to each other in a first direction d1, at least two unit cells 72, 72" arranged next to each other in a second direction d2, and at least two unit cells 72, 72"' arranged next to each other in a third direction d3, where the first, second, and third directions d1, d2, d3 are arranged at an angle to each other. For example, as shown, if the unit cell 72 has a cubic shape, the three directions d1, d2, d3 are orthogonal, and if the unit cell 72 has a tetrahedral shape, the three directions extend at angles of 120 degrees relative to one another.

[0155] According to some embodiments, one of the first, second and third directions d1, d2, d3 coincides with the first axis 4.

[0156] According to some embodiments, different basic unit cells may be superimposed. For example, an FCC unit cell may be added to a BCC unit cell, and the FCC unit cell may be fabricated simultaneously, for example, by additive manufacturing. Furthermore, a three-dimensional structure may comprise different types of unit cells occupying the same volume. By different types of unit cells, for example, it is meant unit cells having different structures that are sized differently, for example, members of different thicknesses.

[0157] Figures 3a-c show an electric fluid heater 30 according to an embodiment. In Figure 3a, the electric fluid heater 30 is shown in an end view, i.e., a view showing either the inlet or outlet end of the electric fluid heater 30. In Figure 3b, a cross section of the electric fluid heater 30 is shown along line BB in Figure 3a. In Figure 3c, a cross section along the electric fluid heater 30 is shown along line CC in Figure 3b.

[0158] The electric fluid heater 30 includes a housing 32. The housing 32 has a fluid inlet 34 and a fluid outlet 36. A fluid flow path for heating the fluid is defined within the housing 32. The fluid flow path extends from the fluid inlet 34 to the fluid outlet 36. The fluid flow path is indicated by the bold arrows in Figures 3b and 3c.

[0159] The housing 32 may be formed by a pipe or a section of a pipe. The housing 32 may be a pressure vessel.

[0160] The heating element 2 according to any one of the aspects and / or embodiments discussed herein is arranged with the first axis 4 of the heating element 2 extending along at least a portion of the fluid flow path, i.e., the first axis 4 of the heating element 2 extends at least partially parallel to the fluid flow path.

[0161] Thus, the heating element 2 comprises, inter alia, heating panels 6 electrically connected to each other via electrical connectors 14. The heating element 2 has first and second sides 10, 12 extending substantially parallel to a first axis 4. For example, the heating element 2 may be a heating element 2 comprising heating panels 6 arranged along a row 9, as discussed above with reference to Figures 1a-1c.

[0162] In the embodiment of Figures 3a-3c, only one heating element 2 is arranged within the housing 32. In alternative embodiments, two or more heating elements may be arranged within the housing. Such two or more heating elements may be arranged in series along the fluid flow path and / or in parallel along the fluid flow path. That is, the fluid to be heated may flow sequentially through the two or more heating elements and / or in parallel through the heating elements.

[0163] According to some embodiments, such as the embodiment shown, the electric fluid heater 30 may include insulation 38 arranged along at least a portion of the fluid flow path. In this manner, the heating element 2 may be thermally and electrically isolated from the housing of the electric fluid heater 30. The fluid flow path may also be bounded by the insulation 38, i.e., the insulation 38 may define the fluid flow path within at least a portion of the housing 30.

[0164] The heating element 2 can be easily positioned within the housing 30 with the first and second sides 10, 12 of the heating element 2 extending substantially parallel to the first axis 4. Thus, the heating element 2 can be easily inserted into and removed from the housing 30, facilitating assembly and / or maintenance of the electric fluid heater 30. The heating element 2 can be inserted into or removed from insulation 38 arranged within the housing 30. Alternatively, the heating element 2 can be inserted into or removed from the housing along with the insulation 38.

[0165] The electric fluid heater 30 includes two terminals 20 for connecting electrical power to the heating element 2 and the heating panel 6 .

[0166] The terminals 20 may form part of the heating element 2. Alternatively, the terminals 20 may form a separate part mounted separately within the electric fluid heater 30 and connected to the heating panel 6 at each end of the heating element 2. A further option may be that the terminals 20 comprise two or more components, some of the terminal components forming part of the heating element 2 and other terminal components mounted separately within the electric fluid heater 30.

[0167] Terminals 20 may extend laterally through a wall of housing 32 to the exterior of housing 32, as shown in Figures 3a-3c. Alternatively, one or both terminals 20 may extend to the exterior of housing 32 via fluid inlet 34 and / or fluid outlet 36.

[0168] Figures 4a and 4b show an electric fluid heater 30 according to an embodiment. In Figure 4a, the electric fluid heater 30 is shown in an end view, i.e., a view showing the inlet or outlet end of the electric fluid heater 30. In Figure 4b, a cross section of the electric fluid heater 30 is shown along line BB in Figure 4a.

[0169] The electric fluid heater 30 is quite similar to the electric fluid heater 30 of the embodiment of Figures 3a-3b, and therefore, the following will mainly discuss the differences between the embodiment of Figures 4a-4b and Figures 3a-3c.

[0170] Again, electric fluid heater 30 includes a housing 32. Housing 32 has a fluid inlet 34 and a fluid outlet 36. A fluid flow path, indicated by the bold arrow, through which fluid may be heated is defined within housing 32. Insulation 38 is disposed along at least a portion of the fluid flow path.

[0171] In the embodiment of Figures 4a-b, two heating elements 2, 2' are arranged in a housing 32. The two heating elements 2, 2' are arranged in parallel along the fluid flow path, i.e. the first axes of each of the heating elements 2 are arranged in parallel to each other and to at least a portion of the fluid flow path.

[0172] Within each heating element 2 , 2 ′, the heating panels 6 are arranged along a row 9 of heating panels 6 .

[0173] The two heating elements 2, 2' are electrically connected in series. A conductive element 40 is arranged between the outermost heating panels 6 arranged at the same ends of the two heating elements 2, 2'. Through the conductive element 40, the two heating elements 2, 2' are electrically connected.

[0174] Again, the electric fluid heater 30 comprises two terminals 20 for connecting electrical power to the heating elements 2, 2'. The terminals 20 are arranged at the same end of the electric fluid heater 30, since the two heating elements 2, 2' are electrically connected in series.

[0175] In an alternative embodiment, the two heating elements 2, 2' may be electrically connected in parallel. This would provide a configuration of an electric fluid heater 30 in which within each heating element 2 the heating panels 6 are electrically connected in series and the two heating elements 2, 2' are connected in parallel.

[0176] Further electrical connection alternatives of the heating elements 2 are also possible. For example, if the electric fluid heater 30 comprises three heating elements 2, the heating elements can be connected to a three-phase AC via a star or delta connection.

[0177] Figures 6a to 6d show four heating elements 2, 2', 2", 2"' according to an embodiment. In Figure 6a the heating elements are shown in isometric view. In Figure 6b the heating elements are shown in end view. Figure 6c shows the heating elements in side view. Figure 6d shows the heating elements in top view.

[0178] The heating elements 2, 2', 2", 2"' in these embodiments are quite similar to the heating elements 2, 2' discussed herein, such as above with reference to Figures 1a-4b.

[0179] Again, each heating element 2, 2', 2", 2''' has an extension along a first axis 4, indicated by a dashed line. Viewed along the first axis 4, each heating element 2, 2', 2", 2''' has a first end 5 and an opposite second end 7.

[0180] Similarly, for the embodiment of Figures 4a-b, the heating elements 2, 2', 2", 2''' are arranged parallel to their respective first axes 4. Fluid to be heated in the heating elements 2, 2', 2", 2''' flows along a fluid flow path parallel to the first axis 4 through the heating elements 2, 2', 2", 2'''.

[0181] Again, each heating element 2, 2', 2", 2''' comprises a row 9 of fluid permeable heating panels 6. The heating panels 6, in this example five heating panels 6 per heating element, are arranged adjacent to one another along the first axis 4 with a spacing 8 between adjacent heating panels 6 within each heating element 2, 2', 2", 2'''. Each heating element 2, 2', 2", 2''' may comprise fewer or more than five heating panels 6.

[0182] Moreover, there are also spacings 21 between adjacent heating panels 6 of adjacent heating elements 2, 2', 2", 2"'.

[0183] Again, each heating element 2 , 2 ′, 2″, 2′′ has a three-dimensional shape bounded in part by a first side 10 and an opposing second side 12 .

[0184] Again, within each heating element 2, 2' the heating panels 6 are electrically connected in series via electrical connectors 14. The electrical connectors 14 are arranged on the first and second sides 10, 12.

[0185] Again, the heating panel 6 of one heating element 2, 2', 2", 2'' is electrically connected in series along a conductive path from the first end 5 to the second end 7 of the heating element 2, 2', 2", 2'', as viewed along the first axis 4, via electrical connectors 14 arranged alternately on the first and second sides 10, 12.

[0186] The four heating elements 2, 2', 2", 2'' are electrically connected in series. Three conductive elements 40 are arranged between the last heating panels of the heating elements 2, 2', 2", 2'' at the first and second ends 7. Via each conductive element 40, two heating elements 2, 2', 2", 2'' are electrically connected in series.

[0187] The first and the last of the heating elements 2, 2''' in the series connection are provided with terminals 20 for connecting power to the heating elements 2, 2', 2", 2'''. Since the four heating elements 2, 2', 2", 2''' are electrically connected in series, the terminals 20 are both arranged at the first end 5, in the implementation shown, at the same end of the first and last heating element 2, 2'''.

[0188] Again, non-conductive spacer elements (not shown) may be arranged between adjacent heating panels 6 of each heating element 2, 2', 2", 2'''. The spacer elements are arranged between the heating panels 6 in such a way that they do not impede, at least not to any significant extent, the flow of the fluid to be heated through the heating elements 2, 2', 2", 2'''.

[0189] Moreover, one or more non-conductive further spacer elements 22 may be arranged between the heating panels 6 of adjacent heating elements 2, 2', 2", 2"'. One such further spacer element 22 is shown diagrammatically in Figure 6b.

[0190] According to some embodiments, such further spacer elements 22 may at least partially separate the flow paths through the heating elements 2, 2', 2", 2"' into separate flow passages.

[0191] Again, the four heating elements 2, 2', 2", 2"' may be arranged within the housing to collectively form a fluid heater.

[0192] Figures 7a and 7b show a heating element 2 according to an embodiment. In figure 7a the heating element 2 is shown in a side view. Figure 7b shows the heating element 2 in a top view.

[0193] The heating elements 2 of these embodiments are quite similar to the heating elements 2, 2', 2", 2"' discussed herein, such as above with reference to Figures 1a-4b and 6a-6d. Therefore, the differences will be primarily discussed below.

[0194] The main difference is that in the embodiment of figures 7a and 7b the heating element 2 comprises two rows 9 of heating panels 6.

[0195] Again, the heating element 2 has an extension along a first axis 4, indicated by a dashed line. Viewed along the first axis 4, the heating element 2 has a first end 5 and an opposite second end 7.

[0196] Again, the heating element 2 comprises a number of fluid-permeable heating panels 6. The heating panels 6, in this example seven heating panels 6 per row 9 of heating panels, are arranged adjacent to one another along the first axis 4 with a spacing 8 between adjacent heating panels 6 within each row 9 of heating panels 6. Each row 9 may comprise fewer or more than seven heating panels 6.

[0197] Additionally, there are also spaces 17 between adjacent heating panels 6 in adjacent rows 9 of heating panels 6 .

[0198] Again, the heating element 2 has a three-dimensional shape bounded in part by a first side 10 and an opposite second side 12 .

[0199] Again, within the heating element 2, the heating panels 6 are electrically connected in series via electrical connectors 14. The electrical connectors 14 are arranged on the first and second sides 10,12.

[0200] According to these and other embodiments including at least two rows 9 of heating panels 6, the at least two rows 9 of heating panels 6 are electrically connected in series along a conductive path from the first end 5 to the second end 7 of the heating element 2, as viewed along the first axis 4, via electrical connectors 14 arranged alternately on the first and second sides 10, 12.

[0201] Some of the electrical connectors 14 extend between adjacent heating panels 6 within a row 9 of heating panels 6 and some of the electrical connectors 14 extend between heating panels 6 of adjacent rows 9 of heating panels 9. Thus, a conductive path meanders through the heating element 2 from the first end 5 to the second end 7.

[0202] In a heating element 2 with only two rows 9 of heating panels 2, as in these embodiments, the two rows of heating panels 6 are electrically connected in series, alternating between adjacent heating panels 6 within the first row and the second row, and alternating between adjacent heating panels 6 of the first and second rows 9, such that all heating panels 6 of the first and second rows 9 are electrically connected in series via a conductive path that meanders from the first end 5 of the heating element 2 to the opposite second end 7 of the heating element 2. Because the heating element 2 with only two rows 9 of heating panels 6, adjacent heating panels 6 of the two adjacent rows 9 are connected to each other via electrical connectors 14 on one of the sides, in these embodiments, on the second side 12. Adjacent heating panels 6 within each row 9 are connected to each other via electrical connectors 14 on the other side, in these embodiments, on the first side 10.

[0203] The heating element 2 is provided with two terminals 20 for connecting electrical power to the heating element 2 .

[0204] Again, non-conductive spacer elements (not shown) may be arranged between adjacent heating panels 6 in each row 9 of heating panels 6. The spacer elements are arranged between the heating panels 6 in such a way that they do not impede, at least not to any significant extent, the flow of the fluid to be heated through the heating elements 2, 2'.

[0205] Moreover, one or more non-conductive further spacer elements (not shown) may be arranged between adjacent heating panels 6 of adjacent rows 9 of heating panels 6 (see FIG. 8b where a similar such further spacer element 19 is shown diagrammatically).

[0206] According to some embodiments, such further spacer elements may at least partially divide the flow path through the heating element 2 into separate flow paths extending parallel to the first axis 4 .

[0207] Again, the heating elements 2 may be arranged within the housing to collectively form a fluid heater.

[0208] According to alternative embodiments, the fluid heater may comprise two or more heating elements 2, as discussed with reference to Figures 7a and 7b, arranged within a housing of the fluid heater. The two or more heating elements may be connected in series or in parallel. In such embodiments, the terminals 20 may be arranged at opposite ends of the fluid heater or at one end of the fluid heater.

[0209] Figures 8a to 8d show two heating elements 2, 2' according to an embodiment. In figure 8a the heating elements 2, 2' are shown in isometric view. In figure 8b the heating elements 2, 2' are shown in end view. Figure 8c shows the heating elements 2, 2' in side view. Figure 8d shows the heating elements 2, 2' in top view.

[0210] The heating elements 2, 2' of these embodiments are quite similar to the heating elements 2, 2' discussed herein, such as the embodiments discussed above with reference to Figures 1a-6d, and in particular with reference to Figures 7a and 7b, and therefore the main differences will be discussed below.

[0211] The main difference is that in the embodiment of Figures 8a to 8d, each heating element 2, 2' comprises three rows 9 of heating panels 6.

[0212] Again, each heating element 2, 2' has an extension along a first axis 4, indicated by a dashed line. Viewed along the first axis 4, each heating element 2 has a first end 5 and an opposite second end 7.

[0213] Again, the two heating elements 2, 2' are arranged with a first axis 4 of each of the two heating elements 2, 2' in parallel.

[0214] In these embodiments, each row 9 includes seven heating panels 6 arranged adjacent to one another along the first axis 4, with spacing 8 between adjacent heating panels 6 within each row 9 of heating panels 6 and spacing 17 between adjacent heating panels 6 in adjacent rows 9 of heating panels 6. Each row 9 may include fewer or more than seven heating panels 6.

[0215] Again, within each heating element 2, 2' the heating panels 6 are electrically connected in series via electrical connectors 14. The electrical connectors 14 are arranged on the first and second sides 10, 12.

[0216] According to these and other embodiments including at least two rows 9 of heating panels 6, the heating panels 6 of the at least two rows 9 of heating panels 6 are electrically connected in series along conductive paths from the first ends 5 to the second ends 7 of the heating elements 2, 2' as viewed along the first axis 4 via electrical connectors 14 arranged alternately on the first and second sides 10, 12.

[0217] Some of the electrical connectors 14 extend between adjacent heating panels 6 within a row 9 of heating panels 6 and some of the electrical connectors 14 extend between heating panels 6 of adjacent rows 9 of heating panels 9. Thus, a conductive path meanders through the heating element 2 from the first end 5 to the second end 7.

[0218] More specifically, when the heating element 2, 2' comprises three or more rows 9 of heating panels 6, i.e. a first outermost row 9', a second outermost row 9"', and at least one intermediate row 9" between the first and second outermost rows 9', 9"', the heating panels 6 of the three or more rows 9 are electrically connected in series via conductive paths passing through the heating elements 2, 2', see FIG. 8b. Connecting the heating panels of adjacent rows, the conductive paths can be arranged to meander through the heating elements across the first axis.

[0219] For example, a heating panel 6 in a first outermost row 9' is electrically connected with an adjacent heating panel 6 in an adjacent intermediate row 9" of heating panels 6 by an electrical connector 14. If the heating element comprises two or more intermediate rows of heating panels, adjacent heating panels in the adjacent intermediate rows are connected by electrical connectors until a second outermost row 9''' is reached and a heating panel 6 in the associated intermediate row 9" is connected with an adjacent heating panel 6 in the second outermost row 9''' by an electrical connector 14. Thus, a series-connected line of heating panels 6 is formed extending across at least three rows 9', 9", 9''' of heating panels 6 and across the first axis 4. These serially connected lines of heating panels 6 are alternately connected by electrical connectors 14 via adjacent heating panels 6 in the first outermost row 9' and adjacent heating panels 6 in the second outermost row 9'' such that all heating panels 6 in at least three rows 9', 9", 9"' are electrically connected in series via a conductive path that meanders from the first ends 5 to the second ends 7 of the heating elements 2, 2'.

[0220] Again, the two heating elements 2, 2' are electrically connected in series. An electrically conductive element 40 is arranged between the heating panels 6 of the heating elements 2, 2' at their second ends 7. Via the electrically conductive element 40, the two heating elements 2, 2' are electrically connected.

[0221] Each of the heating elements 2, 2' comprises a terminal 20 for connecting power to the heating element 2, 2'. Since the two heating elements 2, 2' are electrically connected in series, the terminals 20 are both arranged at the same end of the two heating elements 2, 2', in the embodiment shown, the first end 5.

[0222] Again, non-conductive spacer elements (not shown) may be arranged between adjacent heating panels 6 in each row 9 of heating panels 6. The spacer elements are arranged between the heating panels 6 in such a way that they do not impede, at least not to any significant extent, the flow of the fluid to be heated through the heating elements 2, 2'.

[0223] Also, one or more non-conductive further spacer elements 19 may be arranged between adjacent heating panels 6 of adjacent rows 9 of heating panels 6. Two such further spacer elements 19 are shown diagrammatically in Figure 8b.

[0224] According to some embodiments, such further spacer elements 19 may at least partially separate the flow path through the heating elements 2 , 2 ′ into separate flow paths extending parallel to the first axis 4 .

[0225] Again, the two heating elements 2, 2' may be arranged within the housing to collectively form a fluid heater.

[0226] According to an alternative embodiment, the fluid heater may comprise only one of the heating elements 2, 2' discussed with reference to Figures 8a-d arranged within the housing of the fluid heater. In such an embodiment, the terminal 20 may be arranged at an opposite end of the fluid heater.

[0227] Figure 5 illustrates a method 100 for heating a fluid in an electric fluid heater 30 according to any one of the aspects and / or embodiments discussed herein. Accordingly, in the following, reference is also made to Figures 1a-4b and 6a-8d.

[0228] Method 100 is providing 102 a fluid to the fluid inlet 34; A step 104 of supplying an electric current to at least one heating element 2, 2' to heat the heating panel 6; conducting 106 the fluid along a fluid flow path through the heating panel 6 to the fluid outlet 36; Step 108 directing the fluid from the fluid outlet 36; Includes.

[0229] Thus, the fluid to be heated is provided to the fluid inlet 34 of the electric fluid heater 30 in a providing step 102. The fluid may be provided to the fluid inlet 34 via a conduit devised to conduct the fluid to the electric fluid heater 30 and the fluid inlet 34.

[0230] The step 104 of suitably supplying electrical current to the heating elements 2, 2′ is performed continuously over the period of time that the fluid to be heated is passing through the electric fluid heater 30. The step 104 of supplying electrical current to the heating elements 2, 2′ may be initiated prior to or simultaneously with the step 102 of supplying fluid to the fluid inlet 34.

[0231] During the step 106 of conducting the fluid along the fluid flow path, the fluid is heated by the heating panel 6. The three-dimensional structural members 45 of the heating panel 6 are heated by an electric current, and as the heat passes through the heating panel 6, heat is transferred to the fluid.

[0232] The heated fluid is directed to its downstream use in a downstream process that utilizes such heated fluid, step 108, by directing the fluid from the fluid outlet 36. The fluid may be directed from the fluid output 36 via a conduit designed to conduct the heated fluid from the electric fluid heater 30 and the fluid outlet 36.

[0233] According to an embodiment, the fluid may be selected from, for example, but not limited to, air, hydrogen, carbon dioxide, synthesis gas, pyrolysis gas, hydrocarbons, steam, and methane, or combinations thereof.

[0234] According to an embodiment, a heating element as defined above or below, or a heating panel as defined above or below, may be coated with one or more catalytic materials.

[0235] In this manner, the method 100 may be utilized in processes such as preheating process gases and heating for catalytic reactions, for example.

[0236] The foregoing is an illustration of various exemplary embodiments, and it should be understood that the present invention is defined solely by the appended claims. Those skilled in the art will appreciate that the exemplary embodiments may be modified and that different features of the exemplary embodiments may be combined to produce embodiments other than those described herein without departing from the scope of the present invention, as defined by the appended claims.

Claims

1. A heating element (2) for an electric fluid heater (30), the heating element (2) having an extension along a first axis (4) and comprising fluid-permeable heating panels (6), the fluid-permeable heating panels (6) extending at an angle relative to the first axis (4) within a range of 45 to 90 degrees and arranged adjacent to one another along the first axis (4) with a space between adjacent heating panels (6); Each heating panel (6) comprises a three-dimensional structure, said three-dimensional structure comprising a number of members (45) of at least one electrically conductive material; the heating element (2) has a three-dimensional shape partially bounded by a first side (10) and an opposite second side (12), the first and second sides (10, 12) extending substantially parallel to the first axis (4), and the heating panel (6) extending between the first and second sides (10, 12); the heating panels (6) are electrically connected in series via electrical connectors (14) arranged on the first and second sides (10, 12); The three-dimensional structure comprises at least three members (45) arranged one after the other along the first axis (4) and connected to each other at nodes (47). Heating element (2).

2. 2. The heating element (2) of claim 1, wherein an electrically conductive path is provided through the heating element (2) by the heating panel (6) and the electrical connector (14), the heating element (2) has a length along the first axis (4), and the electrically conductive path is longer than the length along the first axis (4).

3. 2. The heating element (2) of claim 1, wherein the heating panels (6) are electrically connected in series only via the electrical connectors (14) arranged on the first and second sides (10, 12).

4. The heating element (2) according to claim 1, wherein each of said heating panels (6) is the result of an additive manufacturing process.

5. The heating element (2) of claim 1, wherein the electrical connector (14) is the result of an additive manufacturing process.

6. 2. A heating element (2) according to claim 1, comprising at least two heating panels (6).

7. 2. The heating element (2) according to claim 1, comprising at least two rows (9) of heating panels (6) arranged adjacent to each other along said first axis (4).

8. 8. The heating element (2) according to claim 7, wherein each of said at least two rows (9) of heating panels (6) comprises at least two heating panels (6).

9. 8. The heating element (2) of claim 7, wherein the at least two rows (9) of heating panels (6) are electrically connected in series along conductive paths from a first end (5) of the heating element (2) to an opposite second end (7) of the heating element (2) via the electrical connectors (14) arranged alternately on the first and second sides (10, 12), some of the electrical connectors (14) extending between adjacent heating panels (6) within a row (9) of heating panels (6), and some of the electrical connectors (14) extending between heating panels (6) of adjacent rows (9) of heating panels (6).

10. 2. The heating element (2) of claim 1, wherein the thickness of the member (45) is in the range of 0.05 to 10 mm, or in the range of 0.1 to 4 mm, or in the range of 0.2 to 1 mm, and the length of the member (45) is in the range of 0.1 to 50 mm, or in the range of 0.2 to 15 mm, or in the range of 0.5 to 5 mm.

11. 2. The heating element (2) of claim 1, wherein the members (45) are connected to one another at nodes (47) to form multiple unit cells (25).

12. 2. The heating element (2) of claim 1, comprising non-conductive spacer elements (16) arranged between adjacent heating panels (6) of the row (9) of heating panels at the first and second sides (10, 12).

13. Along the first side (10), one of the electrical connectors (14) extends between two adjacent heating panels (6) to form a pair (18) of heating panels (6), and one of the spacer elements (16) is arranged between the pair (18) of heating panels (6) and a further adjacent heating panel (6'); 13. The heating element (2) of claim 12, wherein along the second side (12), one of the spacer elements (16) is arranged between two heating panels (6) of the pair (18) of heating panels (6), and one of the electrical connectors (14) extends between one of the heating panels (6) of the pair (18) of heating panels (6) and the further adjacent heating panel (6').

14. 2. The heating element (2) of claim 1, wherein the heating element (2) comprises at least two rows (9) of heating panels (6) and at least one further non-conductive spacer element (19) arranged between adjacent heating panels (6) of adjacent rows (9) of heating panels (6).

15. 2. The heating element (2) of claim 1, wherein the heating panel (6) is configured to be electrically heated to a temperature of up to 1450 degrees Celsius, up to a temperature of up to 1900 degrees Celsius, or up to a temperature in the range of 1700-1900 degrees Celsius, or up to a temperature in the range of 1600-2000 degrees Celsius.

16. A first heating panel (6') the three-dimensional structure, the cross-sectional area, thickness, or width of said member (45); the size, shape, or number of voids in said heating panel (6', 6"); The length of the heating panel (6', 6") along the first axis (4).

2. The heating element (2) according to claim 1, which differs from the second heating panel (6") in any one or combination of:

17. 2. The heating element (2) according to claim 1, wherein the three-dimensional structure is a free-standing structure.

18. 18. An electric fluid heater (30) comprising at least one heating element (2) according to any one of claims 1 to 17, and a housing (32) having a fluid inlet (34) and a fluid outlet (36), wherein a fluid flow path for heating a fluid is defined within the housing (32), and the at least one heating element (2) is arranged with a first axis (4) of the at least one heating element (2) extending along at least a portion of the fluid flow path.

19. The electric fluid heater (30) of claim 18, comprising insulation (38) arranged along at least a portion of the fluid flow path.

20. 20. A method (100) for heating a fluid in an electric fluid heater (30) as recited in claim 18, comprising: supplying (102) a fluid to said fluid inlet (34); supplying (104) an electric current to the at least one heating element (2) to heat the heating panel (6); conducting (106) the fluid along the fluid flow path through the heating panel (6) to the fluid outlet (36); directing (108) the fluid through the fluid outlet (36); A method (100) comprising:

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