Electric fluid heater

Abstract

An electric fluid heater is disclosed with a fluid-conducting housing, in which at least one tubular heating element each with a plurality of coils is arranged. An inner region which preferably extends along a coil axis is delimited by the coils. According to the invention, a displacer body arrangement with at least one displacer body is provided in the inner region, wherein a flow region for the fluid is formed on the outer circumference of the displacer body arrangement. The coils are also arranged in the flow region. An interior space arrangement with at least one interior space of the displacer body arrangement is separated from the flow region of the fluid largely or completely in a fluid-tight manner. A transverse flow (that is to say, transversely with respect to the coil longitudinal axis) is very substantially or completely avoided.

Description

[0001] Electric fluid heater

[0002] Description

[0003] Technical area

[0004] The present invention relates to an electric heater for fluids, in particular for liquids, in particular for cooling liquids.

[0005] WO 2011 / 054970 A2 discloses such an electric fluid heater. Three tubular heaters each form several coils along a common coil axis, with the coils arranged in a housing through which the fluid flows. The fluid thus flows around the coils and is heated in the process.

[0006] An embodiment with a fluid guide is shown in which a tubular section is arranged in the housing inside the coils along the coil axis. The fluid to be heated initially flows inside the tubular section along the coil axis, from there radially outward through through-holes to the outer circumference of the tubular section, and finally back along the outer circumference of the tubular section. Since the coils of the tubular heating elements are arranged on the outer circumference of the tubular section, this is also where the fluid first comes into contact with the coils. Provided on the circumference of the tubular section are outer strips that extend along the tubular section and against which the tubular heating elements can be supported. The outer strips can also perform a flow-guiding function.

[0007] The disadvantage of such electric fluid heaters is the cross flow and the resulting limited power density.

[0008] The object of the present invention is to increase the power density of such electric fluid heaters. This object is achieved by an electric fluid heater having the features of claim 1. Further advantageous embodiments are the subject of the dependent claims.

[0009] The claimed electric fluid heater has a fluid-conducting housing in which at least one tubular heater, each with a plurality of coils, is arranged. The coils delimit an inner region, which preferably extends along a coil axis. According to the invention, a displacement body arrangement with at least one displacement body is provided in the inner region, on whose outer circumference a flow region for the fluid is formed. The coils are also arranged in the flow region. An interior arrangement with at least one interior space of the displacement body arrangement is largely or completely separated from the flow region of the fluid in a fluid-tight manner. Largely separated means, for example, that the interior arrangement is 90%, preferably 95%, surrounded by fluid-tight walls. Cross-flow (i.e., transverse to the longitudinal coil axis) is largely or completely avoided.The operating principle of the invention is thus a minimization of the dead volume and a reduction of the flow cross-section. This results in an increase in the flow velocity. The power density of the fluid heater according to the invention is thus increased, thus increasing the heat transfer to the fluid and / or reducing the installation space or the device complexity. Thus, in one variant of the invention, the number of tubular heaters known from the prior art is reduced.

[0010] Manufacturing technology is simple if the coils form a circular cylindrical shape, which also means that the inner area has a circular cylindrical shape.

[0011] The displacement body arrangement is technically simple and is supported on the spirals.

[0012] If the housing has two opposing housing end walls, preferably formed on a trough-like housing part, the displacement body arrangement extends over at least 90%, preferably over at least 95%, of the distance between the two housing end walls in order to largely prevent crossflow. The displacement body arrangement can also be supported on the two housing end walls.

[0013] In a first embodiment of the invention, which is simple to manufacture, the (preferably exactly one) displacement body is a tube. The tube can be cylindrical, i.e., have a uniform cross-section along its length, or it can have a reduced diameter (constriction). If more than two tubular heaters are provided, more than one reduced diameter (constriction) can also be provided.

[0014] If the end sections of the tube are each spaced apart from the two opposing housing end walls, then two end covers are required to form the largely or completely fluid-tight wall according to the invention, each facing one of the two housing end walls. Alternatively, an internal partition wall can also be provided in the tube. If more than two tubular heaters are provided, more than one internal partition wall can also be provided.

[0015] In a second embodiment of the invention, two or more displacement bodies are provided. The displacement bodies can be essentially identical in terms of manufacturing technology and, in the case of two displacement bodies, can be arranged, for example, as a mirror image of one another.

[0016] In one embodiment of the second variant, the displacement bodies are respective cups, each having a bottom.

[0017] In the case of two cups, the two bottoms can face each other. In this case, the interior arrangement has two separate interior spaces. Alternatively, each bottom can also be arranged adjacent to a respective housing end wall. In this case, the two cups can be fastened to one another at their respective circumferential edges and / or inserted into one another. The two cups then together form a tubular displacement body arrangement, with the interior arrangement in this case having exactly one interior space. In particularly preferred developments, the at least one displacement body (e.g. tube or cup) has a plurality of longitudinal ribs distributed over the casing. In the case of the cylindrical tube or in the case of the cup, these can extend over the entire length of the displacement body, e.g. if they form contact sections with all the coils of the tubular heaters, or if they form flow elements with a maximum length.Alternatively, the longitudinal ribs can also extend only over a partial length of the displacement body, e.g. if they only form contact sections for some coils of the tubular heater.

[0018] It is also possible to provide exactly two longitudinal ribs opposite one another, which in a specific embodiment are shaped (evenized) in such a way that an oval cross-section of the tube results.

[0019] To enable or improve heat transfer from the inner surfaces of the coils to the fluid, it is important that internal flow zones remain between the longitudinal ribs, for example, formed as longitudinal grooves, through which the fluid can flow between the coils and the shell of the respective displacement body and absorb heat. Such internal flow zones also reduce unwanted heat input into the interior.

[0020] According to a particularly preferred first basic principle of the invention, the interior of the displacement body arrangement is a rest space into which the fluid penetrates. For this purpose, the displacement body arrangement has at least one opening. At least one of the openings can be an elongated hole or slot.

[0021] For example, during commissioning or after disassembly of the fluid heater, it is important that air can escape from the housing and, in the first basic principle of the invention, also from the fluid resting space, so that the resting space is also completely vented through at least one opening. The elongated hole or slot can be incorporated into the casing of the displacement body (tube or cup) and / or extend approximately parallel to a spiral axis.

[0022] In the case of a cup, at least one of the openings can also be located at the bottom of the cup. In the case of a tube, at least one of the openings can also be located at the end cover of the tube, so that the fluid can penetrate into the rest chamber from a region between the end cover and the adjacent housing end wall and fill it. These openings can be formed by slots arranged between triangular or circular segment-shaped sections of the cover.

[0023] According to a second basic principle of the invention, the displacement body arrangement can also be formed by a fluid-tight tube, so that the interior of the tube is separated from the fluid. In this case, the tube must be connected in a fluid-tight manner to the two housing end walls, and at least one of the housing end walls has an opening so that the interior is connected to the ambient air.

[0024] Short description of the characters

[0025] Fig. 1 shows an electric fluid heater according to the invention in a perspective view from below;

[0026] Fig. 2 shows the fluid heater from Fig. 1 with a first variant of the displacement body arrangement in a longitudinal section;

[0027] Fig. 3 shows the fluid heater from Fig. 1 with a second variant of the displacement body arrangement in a longitudinal section;

[0028] Fig. 4 shows the fluid heater from Fig. 1 with a third variant of the displacement body arrangement in a longitudinal section;

[0029] Fig. 5 shows the electric fluid heater from Fig. 1 with a first embodiment of a two-part displacement body arrangement in a longitudinal section;

[0030] Fig. 6 shows the fluid heater from Fig. 5 in a cross section;

[0031] Fig. 7 shows one of the two displacement bodies from Figs. 5 and 6; Fig. 8 shows a different embodiment of a one-piece displacement body arrangement for use in the fluid heater from Fig. 1;

[0032] Fig. 9 shows a further embodiment of a one-piece displacement body arrangement for use in the fluid heater of Fig. 1;

[0033] Fig. 10 shows a further embodiment of a one-piece displacement body arrangement for use in the fluid heater of Fig. 1;

[0034] Fig. 11 shows a further embodiment of a one-piece displacement body arrangement for use in the fluid heater of Fig. 1;

[0035] Fig. 12 shows a further embodiment of a one-piece displacement body arrangement for use in the fluid heater of Fig. 1;

[0036] Fig. 13 shows a further embodiment of a one-piece displacement body arrangement for use in the fluid heater of Fig. 1; and

[0037] Fig. 14 shows an embodiment of a two-part displacement body arrangement for use in the fluid heater of Fig. 1;

[0038] Fig. 15 shows a further embodiment of a two-part displacement body arrangement for use in the fluid heater of Fig. 1; and

[0039] Fig. 16 shows a further embodiment of a two-part displacement body arrangement for use in the fluid heater of Fig. 1.

[0040] Description of the embodiments

[0041] Fig. 1 shows an electric fluid heater 100 according to the invention in a perspective view from below. The fluid heater 100 has a housing, in whose fluid space the variants and exemplary embodiments of the displacement body arrangement according to the invention described with reference to the following Figures 2 to 16 can be realized.

[0042] The housing is composed of a trough-like housing part 6 and a substantially flat housing cover 10. In order to seal the fluid space defined by the trough-like housing part 6 and the housing cover 10 in a fluid-tight manner, these two housing parts 6, 10 are integrally connected to one another, e.g., welded or soldered. On an underside of the trough-like housing part 6 (top in Fig. 1), two connections 8 for the fluid are formed at a distance from one another, one of which serves as an inlet and the other connection 8 as an outlet. Furthermore, two fastening tabs 6a are attached to the trough-like housing part 6, with which the fluid heater 100 can be fastened, e.g., in a vehicle whose coolant is to be heated.

[0043] The housing cover 10 protrudes on one side (right in Fig. 1) beyond the trough-like housing part 6. A high-voltage electrical connector 10a for supplying power to the fluid heater 100 is screwed to this projection, and a ground bolt 10b is welded to it. Furthermore, a low-voltage electrical connector 10c is screwed to the projection, via which the LIN communication with the fluid heater 100 takes place.

[0044] On the upper side of the housing cover 10, facing away from the fluid chamber in the operating position, an electronics housing 11 is provided, which is tightly attached to the housing cover 10 by means of crimped tabs. The crimped tabs are formed evenly around the edge of the electronics housing 11 and completely encompass the edge of the housing cover 10. An electronics installation space is defined by the housing cover 10 and the electronics housing 11. This space contains (not visible) electronics, power distribution bars, and switching elements, e.g., IGBTs.

[0045] General variants and more specific embodiments of the displacement body arrangement according to the first basic principle of the invention are described with reference to Figures 2 to 16. The first basic principle is characterized in that at least one rest chamber 25, into which the fluid penetrates, is formed in the at least one interior space of the displacement body arrangement.

[0046] Figures 2 to 4 each show the housing of the fluid heater 100 from Fig. 1. The respective coils of two tubular heaters 2 extend along a coil axis 4. Two end sections with electrical connections of the two tubular heaters 2 extend in a sealed manner through the housing cover 10 into the electronics installation space of the electronics housing 11 (shown in Fig. 1), wherein only one end section with the electrical connection is shown in Figures 2 to 4.

[0047] Fig. 2 shows the housing of the fluid heater 100 from Fig. 1 with a first variant of the displacement body arrangement. This consists of a tube 101; 201; 301; 401; 501; 601, which is radially spaced from the coils of the tubular heaters 2 and is in preferably sealing contact with the two housing end walls 12 of the preferably trough-like housing part 6. For this purpose, the tube 101; 201; 301; 401; 501; 601 is clamped or clamped between the two housing end walls 12. The initial filling of the rest space 25 created in this way takes place via radial openings 22 in the tube 101; 201; 301; 401; 501; 601. During operation of the fluid heater 100, cross flow is largely avoided.

[0048] Fig. 3 shows the housing of the fluid heater 100 from Fig. 1 with a second variant of the displacement body arrangement. This consists of a tube 101; 201; 301; 401; 501; 601, which is clamped or radially clamped to the coils of the tubular heaters 2. The two end faces of the tube 101; 201; 301; 401; 501; 601 are spaced apart from the respective housing end walls 12 of the preferably trough-like housing part 6. The initial filling of the rest space 25 thus created takes place via the two annular openings 23 in the region of the housing end walls 12. During operation of the fluid heater 100, a slight cross-flow is possible, namely along the two housing end walls 12 and from one annular opening 23 through the rest space 25 to the other annular opening 23.

[0049] In a sub-variant of the second variant, a front cover 26 is provided on the tube 401; 501, or an inner partition wall is provided inside the tube 101; 201; 301; 601 at any location along the spiral axis 4 (neither shown in Fig. 3). An opening is provided in the cover 26 or in the partition wall.

[0050] Fig. 4 shows the housing of the fluid heater 100 from Fig. 1 with a third variant of the displacement body arrangement. This consists of two cups 1; 701; 801, which are clamped or clamped radially on the coils of the respective tubular heater 2. The bottoms 16 of the two cups 1; 701; 801 are adjacent to one another and are spaced slightly apart. The front edges of the two cups 1; 701; 801 are spaced apart from the respective housing end wall 12 of the preferably trough-like housing part 6. The initial filling of the two rest spaces 25 created in this way takes place via the space between the edge of the cup 1; 701; 801 and the adjacent housing end wall 12. During operation of the fluid heater 100, a slight cross-flow is possible directly along the two housing end walls 12 and between the bottoms 16 of the cups 1; 701; 801.

[0051] In a sub-variant of the third variant (not shown in Fig. 4), the two cups 1; 701; 801 are adjacent to each other to minimize crossflow. The two bottoms 16 or, alternatively, the two edges of the cups 1; 701 can be adjacent to each other.

[0052] Hereinafter, more concrete embodiments of the present invention will be described on the basis of the accompanying figures.

[0053] Fig. 5 shows the electric fluid heater 100 according to the invention with a first embodiment of a displacement body arrangement which is formed from two independent displacement bodies which are designed as a respective cup 1.

[0054] Two tubular heating elements 2, each with a plurality of coils, are provided, resulting in a circular-cylindrical inner region extending along a coil axis 4. Such arrangements are known in principle from the prior art, so that further explanations are unnecessary.

[0055] The two cups 1 of the displacement body arrangement are each inserted into a tubular heater 2. Two cups of different lengths can also be inserted, of which the longer cup is inserted into both tubular heaters 2.

[0056] The fluid heater according to Fig. 5 has the trough-like housing part 6, on the underside of which the two connections 8 for the fluid, preferably a cooling liquid, are formed at a distance from one another along the coil axis 4. At an upper side, the trough-like housing part 6 is tightly closed with a housing cover 10. Two end sections with electrical connections of the two tubular heaters 2 extend outwardly through the housing cover 10 in a sealed manner, whereby only one end section with the electrical connection is shown in Fig. 5.

[0057] Each cup 1 has a shell and a base 16, with a rounded area formed on the shell adjacent to the base 16. The two cups 1 are constructed identically and inserted into the inner area of ​​the spirals in a mirror-symmetrical manner, so that the two bases 16 face each other and are spaced slightly apart. The two edges of the cups 1 each rest against a housing end wall 12 of the trough-like housing part 6. Particularly due to the distance between the two bases 16, the displacement body arrangement shown extends over at least 90%, preferably over at least 95%, of the distance between the two housing end walls 12 along the spiral axis 4.

[0058] Fig. 6 shows the fluid heater from Fig. 5 in a cross-section looking in the direction AA (as per Fig. 5) along the coil axis 4. This shows the bottom 16 of a cup 1 and along the flow region 18, 20 for the fluid on the outer circumference of the cup 1. It can be seen that the cup 1 has four longitudinal ribs 17 distributed around the circumference of its shell, with which the cup 1 is held, e.g. clamped, in the coils of the tubular heater 2, and that four longitudinal grooves remain between the four longitudinal ribs 17. The longitudinal grooves each form an inner flow region 18 for the fluid, through which the fluid can flow between the coils and the shell of the cup 1 and absorb heat. These inner flow regions 18 also reduce the unwanted heat input into the interior of the respective cup 1. An outer flow region 20 is formed on the outer circumference of the coils.

[0059] According to the first basic principle of the invention, the cup 1 has four openings formed as through-holes 22, which are arranged in the rounded region of the shell. Fig. 7 shows one of the two cups 1 from Figures 5 and 6. Of the four through-holes 22 in the rounded region of the shell, only one through-hole 22 can be seen. Furthermore, it is shown that the shell of the cup 1 has the four longitudinal ribs 17, with an opening formed as a slot 24 being provided on one of the longitudinal ribs 17. The total of five openings allow the fluid from the flow region 18, 20 to penetrate into the interior of the cup 1, whereby the interior is separated by 90%, preferably 95%, from the flow region 18, 20 with fluid-tight walls, whereby the fluid can penetrate into the rest space 25 thus formed.

[0060] Fig. 8 shows a different embodiment of a displacement body arrangement formed by a tube 101 intended for insertion into the inner region of the coils of the two tubular heaters 2 from Fig. 2 or 3. The tube 101 has a cylindrical shape with five longitudinal ribs 17 distributed unevenly around the circumference and a corresponding number of inner flow sections 18.

[0061] The upper longitudinal rib 17 in Fig. 8 is manufactured with an overlap, so that a slot 17 can be created there. Furthermore, the front edges of the tube 101 do not lie fluid-tight against the two housing end walls 12 (shown in Fig. 1), so that openings are also created there, whereby the interior forms a rest space for the fluid.

[0062] The tube 101 of Fig. 8 can be installed with the slot serving as an opening in the first variant (according to Fig. 2) and with the slot closed in the second variant (according to Fig. 3).

[0063] Fig. 9 shows a further embodiment of a one-piece displacement body arrangement formed by a tube 201 for insertion into the inner region of the coils of the tubular heaters 2 from Figures 2 and 3. The tube 201 has a cylindrical shape with eight longitudinal ribs 17 distributed around the circumference and a corresponding number of inner flow sub-regions 18. Between two (upper in Fig. 9) longitudinal ribs 17, an inner flow sub-region 18 is provided which is deeper than the other inner flow sub-regions 18.

[0064] Since the end edges of tube 201 do not abut fluid-tight against the two housing end walls 12 (shown in Fig. 1), openings 23 are created there, forming a resting space 25 for the fluid. Thus, tube 201 of the second variant (as shown in Fig. 3) is installed.

[0065] The pipe 201 of Fig. 9 can also be installed in the first variant (according to Fig. 2) after the introduction of openings in the casing.

[0066] Fig. 10 shows a further embodiment of a one-piece displacement body arrangement formed by a tube 301 for insertion into the inner region of the coils of the tubular heaters 2 from Figures 2 and 3. Similar to the embodiment of Fig. 9, the tube 301 has a cylindrical shape with eight longitudinal ribs 17 evenly distributed around the circumference and a corresponding number of inner flow sections 18.

[0067] Since the end edges of tube 301 do not fit fluid-tight against the two adjacent housing end walls 12 (shown in Fig. 1), openings are created there, forming a fluid-resting space 25 in the interior. Thus, tube 301 of the second variant (as shown in Fig. 3) is installed.

[0068] The pipe 301 of Fig. 10 can also be installed in the first variant (according to Fig. 2) after the introduction of openings in the casing.

[0069] Fig. 11 shows a further embodiment of a one-piece displacement body arrangement formed by a tube 401 for insertion into the inner region of the coils of the tubular heaters 2 from Figs. 2 and 3. The tube 401 corresponds to the tube 101 of Fig. 8, with the difference that it has a cover 26 on each end face, which is formed by triangular or circular segment-shaped cover sections. Due to the two covers 26, the interior space serving as a rest area is largely sealed off according to the invention, even if the two end faces are at a significant distance from the respective housing end walls 12 (shown in Fig. 1).

[0070] The fluid can penetrate into the resting chamber from a region between the end cover 26 of the tube 401 and the adjacent housing end wall 12 and fill it, since the cover 26 has slots 24. These are arranged between triangular or circular segment-shaped sections of the cover 26.

[0071] The pipe 401 of Fig. 11 can be installed in the above-mentioned sub-variant of the second variant (according to Fig. 3).

[0072] Fig. 12 shows a further embodiment of a displacement body arrangement formed by a largely circular-cylindrical tube 501 for insertion into the inner region of the coils of the tubular heaters 2 from Figures 2 and 3. On the outer circumference, a group of four circumferentially distributed longitudinal ribs 17 are provided for each of the two tubular heaters 2. These ribs do not extend over the entire length of the tube 501 and serve as a contact section. This maximizes the cross-section of the inner flow section 18.

[0073] The tube 501 has a cover 26 on each end face. This results in the most extensive closure of the interior space serving as a rest area according to the invention, even if the two end faces of the tube 501 should have a significant distance from the respective housing end walls 12 (shown in Fig. 1).

[0074] The penetration of the fluid into the interior of the tube 501 is made possible by an opening in the cover 26 designed as a through hole 22 and by slots 24 provided on both sides of the longitudinal ribs 17.

[0075] The pipe 501 of Fig. 12 can be installed in the above-mentioned sub-variant of the second variant (according to Fig. 3).

[0076] Fig. 13 shows a further embodiment of a one-piece displacement body arrangement formed by a tube 601 for insertion into the inner region of the coils of the tubular heaters 2 from Figures 2 and 3. Like the tube 301 from Fig. 10, the tube 601 has eight longitudinal ribs 17 evenly distributed around the circumference and a corresponding number of inner flow sections 18. Deviating from this, the tube 601 is not completely cylindrical, but rather a constriction 28 is provided in the middle, whereby a respective cup-like section of the tube 601 is inserted into each of the two tubular heaters 2 (shown in Figures 2 and 3).

[0077] The pipe 601 of Fig. 13 can be installed in the second variant (according to Fig. 3) and after the introduction of openings in the casing also in the first variant (according to Fig. 2).

[0078] For the embodiments illustrated in Figures 8 to 10 and Figure 13, an inner partition wall (not shown) may be provided in the tube 101; 201; 301; 601. In particular, if the front edges at the ends of the tube 101; 201; 301; 601 do not abut the housing end walls 12, crossflow can be prevented.

[0079] Fig. 14 shows a further embodiment of a two-part displacement body arrangement for use in the fluid heater 100 of Fig. 1. Two cups 1 according to Fig. 7 are provided, the bottoms 16 of which abut one another.

[0080] The displacement body arrangement from Fig. 14 with the two cups 1 is installed in the sub-variant of the third variant mentioned with reference to Fig. 4.

[0081] Fig. 15 shows an embodiment of a displacement body arrangement formed by two cups 701 for insertion into the inner region of the coils of the tubular heaters 2 from Fig. 4. The two cups 701 are inserted into one another at their respective circumferential edges. Thus, the two cups 701 together form a tubular displacement body arrangement with precisely one interior space.

[0082] The bases 16 are arranged adjacent to a respective housing end wall 12 (shown in Fig. 4). Each cup 701 has four longitudinal ribs 17 evenly distributed around the circumference and a corresponding number of inner flow sections 18.

[0083] The penetration of the fluid into the interior of the tubular displacement body arrangement is made possible by an opening formed as a through hole 22 in the two bases 16 and by a plurality of slots 24 provided between the longitudinal ribs 17 (in the flow sections 18).

[0084] At least one slot 24 is provided in a shell of the cup 701 at a distance from its edge, and at least one slot 24 extends to the respective edge of the cup 701, whereby two slots 24 formed on different cups 701 can result in a longer slot of the displacement body arrangement.

[0085] The displacement body arrangement from Fig. 15 with the two cups 701 is installed in the sub-variant of the third variant mentioned with reference to Fig. 4.

[0086] Fig. 16 shows a further embodiment of a two-part displacement body arrangement for use in the fluid heater 100 from Fig. 1 with two cups 801 for insertion into the inner region of the coils of the tubular heaters 2 from Fig. 4. The two cups 801 are of identical design and are inserted in a mirror image of each other into the inner region of the respective coil.

[0087] The two cups 801 are adjacent to each other at their respective circumferential edges. Thus, the two cups 801 together form a tubular displacement body arrangement with exactly one interior space.

[0088] The floors 16 are arranged adjacent to and spaced from the respective housing end wall 12 (shown in Fig. 4).

[0089] Each cup 801 has a plurality of longitudinal ribs 17 distributed uniformly around the circumference and a corresponding number of inner flow sections 18. The penetration of the fluid into the interior of the tubular displacement body arrangement is made possible by an opening in the two bottoms 16, designed as a through hole 22.

[0090] The displacement body arrangement from Fig. 16 with the two cups 801 is installed in the sub-variant of the third variant mentioned with reference to Fig. 4.

[0091] In contrast to the fluid heater 100 shown in Figures 1 to 6 with two tubular heaters 2, a housing extended along the coil axis 4 can of course also be provided, in which—similar to the prior art according to WO 2011 / 054970 A2—the coils of three tubular heaters 2 are arranged. Thus, the power compression according to the invention would be specifically represented as a power increase compared to WO 2011 / 054970 A2.

[0092] Of course, a housing extended along the coil axis 4 can also be provided, in which the coils of four or more tubular heating elements 2 are arranged.

[0093] It is also possible for several fluid heaters 100 shown and / or mentioned to be connected in series with their respective connections 8 in order to multiply the power of the fluid heater arrangement thus formed.

[0094] List of reference symbols: 1; 701; 801 cup 2 tubular heater 4 spiral axis 6 trough-like housing part 6a fastening tab 8 connection 10 housing cover 10a high-voltage plug 10b ground bolt 10c low-voltage plug 11 electronics housing 12 housing end wall 16 base 17 longitudinal rib 18 inner flow section 20 outer flow section 22 through hole 23 annular opening 24 slot 25 rest area 26 cover 28 constriction 100 electric fluid heater 101; 201; 301; 401; 501 cylindrical tube 601 tube

Claims

Requirements for electric fluid heaters with a fluid-carrying housing in which several Coils of at least one tubular heating element (2) are arranged, wherein an inner region is bounded by the coils, characterized in that a displacement body arrangement with at least one displacement body (1; 101; 201; 301; 401; 501; 601; 701; 801) is arranged in the inner region, wherein a flow region (18, 20) for the fluid is formed at the outer circumference of the displacement body arrangement, in which the coils are arranged. Electric fluid heater according to claim 1, wherein the displacement body arrangement is supported on the coils. Electric fluid heater according to one of the preceding claims, wherein the housing has two opposing housing end walls (12), which are preferably formed on a trough-like housing part (6), which is preferably closed with a housing cover (10).An electric fluid heater according to claim 3, wherein the displacement body arrangement extends over at least 90%, preferably at least 95%, of the distance between the two housing end walls (12). An electric fluid heater according to claim 3 or 4, wherein the displacement body arrangement is supported on the two housing end walls (12). An electric fluid heater according to any one of the preceding claims, wherein the displacement body is a tube (101; 201; 301; 401; 501; 601). An electric fluid heater according to claim 6, wherein the tube (601) has at least one reduction in diameter or constriction. An electric fluid heater according to claim 6, wherein the tube (101; 201; 301; 401; 501) is cylindrical. An electric fluid heater according to any one of claims 3 to 5 and according to any one of claims 6 to 8, wherein the tube (401) has one or two end caps (26), each facing one of the two housing walls (12), or wherein the tube (101; 201; 301; 601) has at least one internal partition. An electric fluid heater according to any one of claims 1 to 5, wherein the displacement body arrangement comprises two or more displacement bodies. An electric fluid heater according to claim 10, wherein the displacement bodies are cups (1; 701; 801), each having a bottom (16). Electric fluid heater according to one of the preceding claims, wherein the at least one displacement body has several longitudinal ribs (17) distributed around the circumference or shell.An electric fluid heater according to any of the preceding claims, wherein the at least one displacement body has at least one opening (22, 24) through which fluid can enter and fill a resting space (25) formed inside the displacement body assembly or the displacement body. An electric fluid heater according to claim 13, wherein at least one of the openings is an elongated hole or slot (24) arranged approximately parallel to a helical axis (4) and / or provided in a shell of the displacement body. An electric fluid heater according to claim 9 and according to claim 13 or 14, wherein at least one of the openings (22, 24) is arranged on the end cap of the tube (401; 501) or in the at least one inner partition.

16. An electric fluid heater according to claim 12 and according to one of claims 13 to 15, wherein at least one of the openings (22) is arranged at the bottom (16) of the cup (701; 801).

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