WO2023247557A1

WO2023247557A1 - Electric fluid heater

Info

Publication number: WO2023247557A1
Application number: PCT/EP2023/066671
Authority: WO
Inventors: Alaa HARMOUCH
Original assignee: Dbk David + Baader Gmbh
Priority date: 2022-06-24
Filing date: 2023-06-20
Publication date: 2023-12-28

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

Electric fluid heater

Description

Technical area

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

Such an electric fluid heater is disclosed in WO 2011/054970 A2. Three tubular heating elements each form several turns along a common helical axis, with the helixes being arranged in a housing through which the fluid flows. This means that the fluid flows around the coils and is heated in the process.

An exemplary embodiment with a fluid guide is shown, in which a pipe part is arranged in the housing inside the coils along the coil axis. The fluid to be heated initially flows inside the tube part along the helical axis, from there through through recesses radially outwards to the outer circumference of the tube part and finally back on the outer circumference of the tube part. Since the coils of the tubular heating elements are arranged on the outer circumference of the tubular part, the first contact of the fluid with the coils also occurs there. Outer strips are provided on the circumference of the tubular part, which extend along the tubular part and on which the tubular heating elements can be supported. The outer strips can also take on a flow guiding function.

The disadvantage of such electrical fluid heaters is the cross flow and the resulting limited power density.

The object of the present invention is to increase the power density of such electrical fluid heaters. The task is solved by an electric fluid heater with the features of claim 1. Further advantageous refinements are the subject of the subclaims.

The claimed electric fluid heater has a fluid-carrying housing in which at least one tubular heating element, each with several coils, is arranged. An inner area is delimited by the coils, 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 the outer circumference of which a flow region for the fluid is formed. The coils are also arranged in the flow area. An interior arrangement with at least one interior space of the displacement body arrangement is largely or completely separated from the flow area 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. A transverse flow (i.e. across the longitudinal axis of the helix) is largely or completely avoided. The active principle according to the invention is therefore 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, so an increase in heat transfer to the fluid is possible and/or a reduction in the installation space or the expenditure on device technology is possible. In a variant of the invention, the number of tubular heating elements known from the prior art is reduced.

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

The displacement body arrangement is simple in terms of device technology and is supported on the coils.

If the housing has two opposing housing end walls, which are 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, to largely accommodate the cross flow to prevent. The displacement body arrangement can also be supported on the two housing end walls.

In a first embodiment variant of the invention that is simple in terms of production technology, the (preferably exactly one) displacement body is a pipe. 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 heating elements are provided, more than one diameter reduction (constriction) can also be provided.

If the end sections of the tube are each at a distance from the two opposing housing end walls, then in order to form the largely or completely fluid-tight wall according to the invention, two end-side covers are required, each of which faces one of the two housing end walls. Alternatively, there can also be an internal partition in the pipe. If more than two tubular heating elements are provided, more than one inner partition wall can also be provided.

In a second embodiment variant of the invention, two or more displacement bodies are provided. The displacement bodies can simply be essentially the same in terms of production technology, and in the case of two displacement bodies, for example, they can be arranged in mirror images of one another.

In an exemplary embodiment of the second embodiment variant, the displacement bodies are respective cups, each of which has a base.

In the case of two cups, the two bottoms can face each other. Then the interior arrangement has two separate interior spaces. Deviating from this, each base can also be arranged adjacent to a respective housing end wall. The two cups can then be attached to one another at their respective peripheral edges and/or inserted into one another. Then the two cups together form a tubular displacement body arrangement, the interior arrangement in this case having exactly one interior space. In particularly preferred developments, the at least one displacement body (eg tube or cup) has several longitudinal ribs distributed on the jacket. 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, for example if they form contact sections with all the coils of the tubular heating elements, or if they form flow elements with a maximum length. Alternatively, the longitudinal ribs can also only extend over a partial length of the displacement body, for example if they only form contact sections for a few coils of the tubular heating element.

Exactly two opposing longitudinal ribs can also be provided, which in a specific exemplary embodiment are shaped (evened out) in such a way that an oval cross-section of the tube results.

In order to enable or improve the heat transfer from the inside of the coils to the fluid, it is important that inner flow sections remain between the longitudinal ribs, for example as longitudinal grooves, through which the fluid flows between the coil and the jacket of the respective displacement body and can absorb heat. Such inner flow sections also reduce the unwanted heat input into the interior.

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.

For example, when starting up or after dismantling 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 rest area for the fluid, i.e. that the rest area can also be completely vented through the at least one opening he follows. The elongated hole or slot can be made in the jacket of the displacement body (tube or cup) and/or extend approximately parallel to a helical axis.

In the case of the cup, at least one of the openings can also be arranged at the bottom of the cup. In the case of the tube, at least one of the openings can also be arranged on the front cover of the tube, so that the fluid can penetrate into the rest space from an area between the front cover and the adjacent housing end wall and fill it. These openings can be formed by slots which are arranged between triangular or circular segment-shaped sections of the lid.

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 delimited from the fluid. Then the pipe must be connected to the two housing end walls in a fluid-tight manner and at least one of the housing end walls has an opening so that the interior is connected to the ambient air.

Short description of the characters

1 shows an electric fluid heater according to the invention in a perspective view from below;

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

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

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

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

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

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

FIG. 9 shows a further exemplary embodiment of a one-piece displacement body arrangement for use in the fluid heater from FIG. 1;

FIG. 10 shows a further exemplary embodiment of a one-piece displacement body arrangement for use in the fluid heater from FIG. 1;

FIG. 11 shows a further exemplary embodiment of a one-piece displacement body arrangement for use in the fluid heater from FIG. 1;

FIG. 12 shows a further exemplary embodiment of a one-piece displacement body arrangement for use in the fluid heater from FIG. 1;

FIG. 13 shows a further exemplary embodiment of a one-piece displacement body arrangement for use in the fluid heater from FIG. 1; and

14 shows an exemplary embodiment of a two-part displacement body arrangement for use in the fluid heater from FIG. 1;

FIG. 15 shows a further exemplary embodiment of a two-part displacement body arrangement for use in the fluid heater from FIG. 1; and

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

Description of the exemplary embodiments

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 implemented.

The housing is composed of a trough-like housing part 6 and an essentially flat housing cover 10. In order to close the fluid space limited in the trough-like housing part 6 and the housing cover 10 in a fluid-tight manner, these two housing parts 6, 10 are materially connected to one another, for example 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, of which one connection 8 serves as an inlet and the other connection 8 serves 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, for example, in a vehicle whose coolant is to be heated.

The housing cover 10 projects over the trough-like housing part 6 on one side (on the right in FIG. 1). An electrical high-voltage plug 10a for supplying power to the fluid heater 100 is screwed to this projection and a ground bolt 10b is welded. Furthermore, an electrical low-voltage plug 10c is screwed onto the supernatant, via which LIN communication with the fluid heater 100 takes place.

On an upper side of the housing cover 10 facing away from the fluid space in the operating position, an electronics housing 11 is provided, which is fastened tightly to the housing cover 10 by means of flanged tabs. The flanged tabs are formed evenly on the edge of the electronics housing 11 and completely surround the edge of the housing cover 10. An electronics installation space is limited by the housing cover 10 and the electronics housing 11. Electronics, power distribution rails and switching elements, e.g. IGBTs, are installed in this (not visible).

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

Figures 2 to 4 each show the housing of the fluid heater 100 from FIG 10 in the electronics installation space of the electronics housing 11 (shown in FIG. 1), whereby in the Figures 2 to 4 only show one end section with the electrical connection.

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 heating elements 2 and is in preferably sealing contact with the two housing end walls 12 of the preferably trough-like housing part 6 on the front side. The pipe is 101; 201; 301; 401; 501; 601 clamped or clamped between the two housing end walls 12. An initial filling of the rest space 25 created in this way takes place via radial openings 22 of the tube 101; 201; 301; 401; 501; 601. During operation of the fluid heater 100, cross-flow is largely avoided.

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 clamped radially on 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 created in this way takes place via the two annular openings 23 in the area of the housing end walls 12. When the fluid heater 100 is in operation, a small 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.

In a sub-variant of the second variant, there is 401 on the pipe; 501 also a front cover 26 or inside the tube 101; 201; 301; 601 an inner partition wall is provided at any point along the helical axis 4 (both not shown in FIG. 3). An opening is provided in the lid 26 or in the partition.

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 heating element 2. The bottoms 16 of the two cups 1; 701; 801 are adjacent to each other and are a short distance apart from each other. 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 between the edge of the cup 1; 701; 801 and the adjacent housing end wall 12 formed annular opening 23. When the fluid heater 100 is in operation, the cup 1 is located directly along the two housing end walls 12 and between the bottoms 16; 701; 801 a slight cross flow is possible.

In a sub-variant of the third variant (not shown in FIG. 4), the two cups 1; 701 ; 801 adjacent to each other. The two bottoms 16 or, alternatively, the two edges of the cups 1; 701 are adjacent to each other.

More concrete exemplary embodiments of the present invention are described below on the basis of the associated figures.

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

Two tubular heating elements 2 are provided, each with several coils, which results in a circular cylindrical inner region that extends along a coil axis 4. Such arrangements are in principle known from the prior art, so that further explanations are unnecessary.

The two cups 1 of the displacement body arrangement are each inserted into a tubular heating element 2. Two cups of different lengths can also be used, of which the longer cup is inserted into both tubular heating elements 2.

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 helical axis 4. On one top is the trough-like housing part 6 is tightly closed with a housing cover 10. Two end sections with electrical connections of the two tubular heating elements 2 extend in a sealed manner through the housing cover 10 to the outside, with only one end section with the electrical connection being shown in FIG.

Each cup 1 has a jacket and a base 16, with a rounded area being formed on the jacket adjacent to the base 16. The two cups 1 are designed to be identical and are inserted in mirror images of one another in the inner area of the coils, so that the two bottoms 16 face each other and are a short distance apart. The two edges of the cups 1 each rest on a housing end wall 12 of the trough-like housing part 6. In particular because of the distance between the two bases 16 from one another, 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 helical axis 4.

6 shows the fluid heater from FIG Outer circumference of the cups 1. It can be seen that the cup 1 has four longitudinal ribs 17 distributed around the circumference of its jacket, with which the cup 1 is held, for example clamped, in the turns of the tubular heating element 2, and that four longitudinal grooves remain between the four longitudinal ribs 17. The longitudinal channels each form an inner flow section 18 for the fluid, through which the fluid can flow between the coil and the jacket of the cup 1 and absorb heat. These inner flow sections 18 also reduce the unwanted heat input into the interior of the respective cup 1. An outer flow section 20 is formed on the outer circumference of the coils.

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 area of the jacket. Fig. 7 shows one of the two cups 1 from Figures 5 and 6. Of the four through holes 22 in the rounded area of the jacket, only one through hole 22 can be seen. Furthermore, it is shown that the jacket 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 area 18, 20 to penetrate into the interior of the cup 1, whereby the interior is 90%, preferably 95% separated from the flow area 18, 20 with fluid-tight walls, whereby the fluid enters the rest space thus formed 25 can penetrate.

8 shows a different exemplary embodiment of a displacement body arrangement, which is formed by a tube 101 which is intended for insertion into the inner region of the coils of the two tubular heating elements 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.

The upper longitudinal rib 17 in FIG. 8 is made with an overlap so that a slot 17 can result there. Furthermore, the front edges of the tube 101 are not fluid-tight against the two housing end walls 12 (shown in FIG. 1), so that there are also openings there, with which the interior forms a resting space for the fluid.

The pipe 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 closed slot in the second variant (according to FIG. 3).

9 shows a further exemplary 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 heating elements 2 from FIGS. 2 and 3. The tube 201 has a cylindrical shape with eight longitudinal ribs 17 distributed around the circumference and one ent - speaking number of inner flow sections 18. Between two longitudinal ribs 17 (upper in FIG. 9) there is an inner flow section 18 which is deeper than the other inner flow sections 18.

Since the front edges of the tube 201 do not rest fluid-tight on the two housing end walls 12 (shown in FIG. 1), openings 23 result there, with which the interior forms a rest space 25 for the fluid. This means that the pipe 201 of the second variant (according to FIG. 3) is installed.

The pipe 201 of FIG. 9 can also be installed in the first variant (according to FIG. 2) after openings have been made in the jacket.

10 shows a further exemplary 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 heating elements 2 from FIGS. 2 and 3. Similar to the exemplary embodiment from FIG. 9, the tube 301 has a cylindrical shape eight longitudinal ribs 17 evenly distributed around the circumference and a corresponding number of inner flow sections 18.

Since the front edges of the tube 301 do not rest in a fluid-tight manner on the two adjacent housing end walls 12 (shown in FIG. 1), openings result there, so that the interior forms a rest space 25 for the fluid. This means that the pipe 301 of the second variant (according to FIG. 3) is installed.

The pipe 301 of FIG. 10 can also be installed in the first variant (according to FIG. 2) after openings have been made in the jacket.

11 shows a further exemplary 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 heating elements 2 from FIGS. 2 and 3. The tube 401 corresponds to the tube 101 of FIG. 8 with the difference that that it has a cover 26 on the front side, which is formed by triangular or circular segment-shaped cover sections. Due to the two covers 26, according to the invention, the interior serving as a rest area is largely closed off even if the two End faces should have a significant distance from the respective housing end walls 12 (shown in FIG. 1).

The fluid can penetrate into the rest space from an area between the front 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.

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

12 shows a further exemplary 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 there are a group of four for each of the two tubular heaters 2 Circumferentially distributed longitudinal ribs 17 are provided, which do not extend over the entire length of the tube 501 and serve as a contact section. The cross section of the inner flow section 18 is thus maximized.

The tube 501 has a cover 26 on each end. According to the invention, this results in the greatest possible closure of the interior serving as a rest area even if the two end faces of the tube 501 should be at a significant distance from the respective housing end walls 12 (shown in FIG. 1). .

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

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

13 shows a further exemplary embodiment of a one-piece displacement body arrangement formed by a tube 601 for insertion into the inner Area of the coils of the tubular heating elements 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. The tube 601 is no different cylindrical throughout, but 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 heating elements 2 (shown in FIGS. 2 and 3).

The pipe 601 of FIG. 13 can be installed in the second variant (according to FIG. 3) and after openings have been made in the jacket also in the first variant (according to FIG. 2).

For the exemplary embodiments shown in FIGS. 8 to 10 and FIG. 13, an inner partition wall (not shown) can be installed in the tube 101; 201 ; 301 ; 601 should be provided. In particular if the front edges at the ends of the tube 101; 201; 301; 601 does not rest on the housing end walls 12, cross flow can be prevented.

FIG. 14 shows a further exemplary embodiment of a two-part displacement body arrangement for use in the fluid heater 100 from FIG. 1. There are two cups 1 according to FIG. 7, the bottoms 16 of which rest against one another.

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.

15 shows an exemplary embodiment of a displacement body arrangement formed by two cups 701 for insertion into the inner region of the coils of the tubular heating elements 2 from FIG. 4. The two cups 701 are inserted into one another at their respective peripheral edges. The two cups 701 thus together form a tubular displacement body arrangement with exactly one interior space.

The floors 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.

The penetration of the fluid into the interior of the tubular displacement body arrangement is made possible by a respective opening designed as a through hole 22 in the two bases 16 and by several slots 24 provided between the longitudinal ribs 17 (in the flow subregions 18).

At least one slot 24 is provided in a jacket 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.

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.

16 shows a further exemplary 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 heating elements 2 from FIG inserted to each other in the inner area of the respective helix.

The two cups 801 rest against each other at their respective peripheral edges. The two cups 801 thus together form a tubular displacement body arrangement with exactly one interior space.

The bases 16 are arranged adjacent and spaced apart from the respective housing end wall 12 (shown in FIG. 4).

Each cup 801 has several longitudinal ribs 17 evenly distributed 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 a respective opening in the two bases 16 designed as a through hole 22.

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.

Deviating from the fluid heater 100 shown in Figures 1 to 6 with two tubular heating elements 2, a housing extended along the helical axis 4 can of course also be provided, in which - similar to the prior art according to WO 2011/054970 A2 - the helices of three tubular heaters 2 are arranged. The performance compression according to the invention would therefore represent a concrete increase in performance compared to WO 2011/054970 A2.

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

Several fluid heaters 100 shown and/or mentioned can also be connected in series with their respective connections 8 in order to multiply the performance of the fluid heater arrangement thus formed.

Reference numeral list: 1; 701; 801 cup 2 tubular heating element 4 helical 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 lid 28 constriction 100 electric fluid heater 101; 201; 301; 401; 501 cylindrical tube 601 tube

Claims

Claims Electric fluid heater with a fluid-carrying housing in which several

Coils of at least one tubular heater (2) are arranged, an inner region being delimited by the coils, characterized in that in the inner region there is a displacement body arrangement with at least one displacement body (1; 101; 201; 301; 401; 501; 601 ; 701 ; 801 ) is arranged, with a flow region (18, 20) for the fluid being formed on 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). Electric fluid heater according to claim 3, wherein the displacement body arrangement extends over at least 90%, preferably over at least 95% of the distance between the two housing end walls (12). Electric fluid heater according to claim 3 or 4, wherein the displacement body arrangement is supported on the two housing end walls (12). Electric fluid heater according to one of the preceding claims, wherein the displacement body is a tube (101; 201; 301; 401; 501; 601). Electric fluid heater according to claim 6, wherein the tube (601 ) has at least one diameter reduction or constriction. An electric fluid heater according to claim 6, wherein said tube (101; 201; 301; 401; 501) is cylindrical. Electric fluid heater according to one of claims 3 to 5 and according to one of claims 6 to 8, wherein the tube (401) has one or two end covers (26), each of which faces one of the two housing end walls (12), or wherein the tube (101; 201; 301; 601) has at least one inner partition. Electric fluid heater according to one of claims 1 to 5, wherein the displacement body arrangement has two or more displacement bodies. Electric fluid heater according to claim 10, wherein the displacement bodies are cups (1; 701; 801) each having a base (16). Electric fluid heater according to one of the preceding claims, wherein the at least one displacement body has a plurality of longitudinal ribs (17) distributed on the circumference or jacket. Electric fluid heater according to one of the preceding claims, wherein the at least one displacement body has at least one opening (22, 24) through which fluid can penetrate into and fill a resting space (25) for the fluid formed inside the displacement body arrangement or the displacement body . Electric fluid heater according to claim 13, wherein at least one of the openings is an elongated hole or slot (24) which is arranged approximately parallel to a helical axis (4) and/or is introduced into a jacket of the displacement body. 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 front cover of the tube (401; 501) or in the at least one inner partition.

16. ktric 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 on the bottom (16) of the cup (701; 801).