CN116804489A

CN116804489A - Electric heater

Info

Publication number: CN116804489A
Application number: CN202310640221.4A
Authority: CN
Inventors: 邱子朝; 石海民; 请求不公布姓名
Original assignee: Zhejiang Sanhua Intelligent Controls Co Ltd
Current assignee: Zhejiang Sanhua Intelligent Controls Co Ltd
Priority date: 2023-05-31
Filing date: 2023-05-31
Publication date: 2023-09-26

Abstract

The application discloses an electric heater, which comprises a shell, a first heating element and a second heating element; the shell comprises a first shell, a second shell and a third shell, the second shell is connected with the first shell, the second shell is connected with the third shell, and the first shell and the third shell are respectively positioned on different sides of the second shell in the thickness direction of the second shell; the electric heater has a first flow chamber and a second flow chamber, the first flow chamber and the second flow chamber being communicable, the first flow chamber and the second flow chamber both being located between the second housing and the third housing, at least one of the first flow chamber and the second flow chamber providing a tortuous flow path for the medium. The arrangement is beneficial to increasing the flow path of the medium, prolonging the heating time and improving the heating effect.

Description

Electric heater

Technical Field

The application relates to the technical field of vehicles, in particular to an electric heater.

Background

The electric heater for the vehicle comprises a shell, a first heating plate and a second heating plate, wherein the shell comprises an upper shell, a lower shell and a cover plate, the first heating plate and the upper shell are fixed to form a first flow channel cavity, the second heating plate and the lower shell are fixed to form a second flow channel cavity, a medium flows in from an inlet of the upper shell, flows through the first flow channel cavity, enters the second flow channel cavity through an interface and flows out from a water outlet of the upper shell. But the medium flows through the first flow channel cavity and the second flow channel cavity rapidly, so that the first heating plate and the second heating plate heat the medium unevenly, the medium can not absorb enough heat, and the heating effect is poor.

Therefore, it is necessary to provide an electric heater having a good heating effect.

Disclosure of Invention

The application aims to provide an electric heater with good heating effect.

The aim of the application is achieved by the following technical scheme:

an electric heater comprising a housing, a first heating element and a second heating element, at least part of the first heating element and at least part of the second heating element being located within the housing;

the shell comprises a first shell, a second shell and a third shell, wherein the second shell is connected with the first shell, the second shell is connected with the third shell, and the first shell and the third shell are respectively positioned on different sides of the second shell in the thickness direction of the second shell;

the electric heater is provided with a first flow channel cavity and a second flow channel cavity, the first flow channel cavity and the second flow channel cavity can be communicated, the first flow channel cavity and the second flow channel cavity are both positioned between the second shell and the third shell, and at least one of the first flow channel cavity and the second flow channel cavity provides a curved flow path for a medium.

According to the electric heater, the first flow channel cavity and the second flow channel cavity are arranged, the first heating element is used for primarily heating the medium in the first flow channel cavity, the medium flows from the first flow channel cavity to the second flow channel cavity, the second heating element is used for secondarily heating the medium in the second flow channel cavity, at least one of the first flow channel cavity and the second flow channel cavity is used for providing a curved flow path for the medium, the flow path of the medium is increased, the heating time is prolonged, the medium can absorb enough heat, and the heating effect is improved.

Drawings

FIG. 1 is a schematic perspective view of an electric heater according to the present application;

FIG. 2 is an exploded view of FIG. 1;

FIG. 3 is another angular perspective view of FIG. 1;

FIG. 4 is an exploded view of FIG. 3;

FIG. 5 is a cross-sectional view of an electric heater of the present application taken along a second passage;

FIG. 6 is a cross-sectional view of an electric heater of the present application taken along a third passageway;

FIG. 7 is a schematic perspective view of the second housing of FIG. 2;

FIG. 8 is a schematic perspective view of the third housing of FIG. 2;

FIG. 9 is a plan view of the first and second heating plates;

FIG. 10 is an enlarged schematic view of area A of FIG. 5;

FIG. 11 is a schematic view of the flow direction of the medium in the second housing;

FIG. 12 is a schematic view of the flow of media in a third housing;

FIG. 13 is a schematic view of a third embodiment of the third housing of the present application;

fig. 14 is a cross-sectional view of the first heating plate, the first heating film;

fig. 15 is a cross-sectional view of the second heating plate and the second heating film.

Detailed Description

Exemplary embodiments of the present application will be described in detail below with reference to the accompanying drawings. If there are several specific embodiments, the features in these embodiments can be combined with each other without conflict. When the description refers to the accompanying drawings, the same numbers in different drawings denote the same or similar elements, unless otherwise specified. What is described in the following exemplary embodiments does not represent all embodiments consistent with the application; rather, they are merely examples of apparatus, articles, and/or methods that are consistent with aspects of the application as set forth in the claims.

The terminology used in the present application is for the purpose of describing particular embodiments only and is not intended to limit the scope of the present application. As used in the specification and claims of the present application, the singular forms "a," "an," or "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.

It should be understood that words such as "first," "second," and the like, used in the description and in the claims of the present application, do not denote any order, quantity, or importance, but rather are names used to distinguish one feature from another. Likewise, the terms "a" or "an" and the like do not denote a limitation of quantity, but rather denote the presence of at least one. Unless otherwise indicated, the terms "front," "rear," "upper," "lower," and the like are used herein for convenience of description and are not limited to a particular location or to a spatial orientation. The word "comprising" or "comprises", and the like, is an open-ended expression, meaning that elements appearing before "comprising" or "including", encompass the elements appearing after "comprising" or "including", and equivalents thereof, and not exclude that elements appearing before "comprising" or "including", may also include other elements. In the present application, if a plurality of the above-mentioned components are present, the meaning of the above-mentioned components is two or more.

The electric heater can convert electric energy into heat energy, is suitable for heating a liquid or vapor-liquid mixture working medium, and the heating means is to electrify the electric heater by electrifying, so that the heating element heats after electrifying and heats the working medium. The electric heater can be used in the technical fields of vehicles and the like and supplies heat for the working condition of the required heat.

Referring to fig. 1 to 13, the present application discloses an electric heater, which comprises a housing 1, a first heating element 2, a second heating element 3, and an electric control board 4, wherein at least part of the first heating element 2 and at least part of the second heating element 3 are located in the housing 1. Wherein the housing 1 has a first cavity 10a and a second cavity 10b, the electric control board 4 is located in the first cavity 10a, and at least part of the first heating element 2 and at least part of the second heating element 3 are located in the second cavity 10b.

Referring to fig. 2, the housing 1 includes a first case 11, a second case 12, and a third case 13, the second case 12 is connected to the first case 11, the second case 12 is connected to the third case 13, and the first case 11 and the third case 13 are respectively located at different sides of the second case 12 in a thickness direction of the second case 12. The first, second and third housings 11, 12 and 13 may be press-formed of a metal material having a supporting and protecting function, and may be press-formed of an aluminum material, for example. The second housing 12 and the third housing 13 are sealed and fixed by a sealing ring 5. In the illustrated embodiment of the present application, referring to fig. 7 and 8, the second housing 12 has the first seal groove 120, the third housing 13 has the second seal groove 130, and the seal ring 5 is mounted to the first seal groove 120 and the second seal groove 130, thereby improving sealability between the second housing 12 and the third housing 13. Of course, in other embodiments, the first housing 11 and the second housing 12 may be sealed and fixed by a seal ring.

The first heating element 2 is welded or adhesively fixed to the second casing 12 in the thickness direction of the second casing 12, and the second heating element 3 is welded or adhesively fixed to the third casing 13 in the thickness direction of the third casing 13.

Referring to fig. 2, the second housing 12 includes a first wall portion 121 and a first peripheral wall 122 extending perpendicularly from the first wall portion 121. The first housing 11 and the third housing 13 are respectively located on different sides in the thickness direction of the first wall portion 121. The first housing 11 and the first peripheral wall 122 are located at the periphery of the first cavity 10a, and the third housing 13 is located at the periphery of the second cavity 10b. Referring to fig. 2 and 4, the first wall portion 121 includes a first side 121a and a second side 121b at opposite sides in a thickness direction thereof, the first side 121a being located in the first cavity 10a, and the second side 121b being located in the second cavity 10b. The first housing 11 is connected to the first peripheral wall 122.

In the illustrated embodiment of the application, the first heating element 2 and the second heating element 3 are spaced between the first wall portion 121 and the third housing 13. The second side 121b faces the first heating element 2 and the second heating element 3 is adjacent to the third housing 13 with respect to the first electric heating element 2.

Referring to fig. 4, the first housing 11 includes a second wall portion 111 and a second peripheral wall 112 extending perpendicularly from the second wall portion 111. The second peripheral wall 112 is fixedly connected to the first peripheral wall 122.

Referring to fig. 5, the electric heater has a first flow path chamber 101 and a second flow path chamber 102, the first flow path chamber 101 and the second flow path chamber 102 being communicable, the first flow path chamber 101 and the second flow path chamber 102 being located between the second housing 12 and the third housing 13. A first flow channel chamber 101 is located between the first heating element 2 and the second housing 12 and a second flow channel chamber 102 is located between the second heating element 3 and the third housing 13.

The first wall portion 121 and the first heating element 2 are located at the periphery of the first flow channel cavity 101, the second heating element 3 and the third housing 13 are located at the periphery of the second flow channel cavity 102, and at least one of the first flow channel cavity 101 and the second flow channel cavity 102 provides a curved flow path for the medium, so that the flow path of the medium is increased, the heating time is prolonged, the medium can absorb enough heat, and the heating efficiency is improved.

In some embodiments, referring to fig. 4, the first wall portion 121 has a first flow channel 1211, the first flow channel 1211 at least partially constituting the first flow channel cavity 101, the first flow channel 1211 opening in the thickness direction of the first wall portion 121 toward the first heating element 2. The first wall portion 121 has a first mounting groove 1212, the first mounting groove 1212 communicates with the first flow channel groove 1211, and the first heating element 2 is mounted to the first mounting groove 1212. The first flow channel 1211 is provided by the first wall 121 such that the first heating element 2 and the first wall 121 enclose a first flow channel chamber 101. In operation, the medium in the first flow channel cavity 101 is heated by the first heating element 2, and heat is supplied to the working condition of the required heat by the medium.

Referring to fig. 4, the first wall portion 121 includes a first groove wall 1201, a second groove wall 1202 opposite to the first groove wall 1201, a first connection wall 1203 connecting one end of the first groove wall 1201 and one end of the second groove wall 1202, and a second connection wall 1204 connecting the other end of the first groove wall 1201 and the other end of the second groove wall 1202, at least part of the walls of the first groove wall 1201, the second groove wall 1202, the first connection wall 1203, and the second connection wall 1204 forming a groove wall of the first flow channel 1211. The first groove wall 1201, the second groove wall 1202, the first connecting wall 1203, and the second connecting wall 1204 together constitute a peripheral wall surface of the first flow channel 1211, and the peripheral wall surface of the first mounting groove 1212 is located on an outer periphery of the peripheral wall surface of the first flow channel 1211. The first connecting wall 1203 and the second connecting wall 1204 are flat walls, and the first connecting wall 1203 is parallel to the second connecting wall 1204.

In the illustrated embodiment of the present application, referring to fig. 4, the first groove wall 1201 includes a first curved wall 120a protruding in a direction approaching the second groove wall 1202, and the second groove wall 1202 includes a second curved wall 120b protruding in a direction approaching the first groove wall 1201, and the first curved wall 120a and the second curved wall 120b give the curved flow path an S shape. Of course, in other embodiments, the first groove wall 1201 may include only the first curved wall 120a protruding in a direction approaching the second groove wall 1202, the first curved wall 120a giving the curved flow path a C-shape.

Specifically, referring to fig. 7, the first curved wall 120a includes a first straight wall 1001, a second straight wall 1002 parallel to the first straight wall 1001, and a first arc-shaped wall 1003 connecting the first straight wall 1001 and the second straight wall 1002, the first straight wall 1001, the second straight wall 1002, and the first connecting wall 1003 being parallel to each other. The second curved wall 120b includes a fifth straight wall 1004, a sixth straight wall 1005 parallel to the fifth straight wall 1004, and a third arc-shaped wall 1006 connecting the fifth straight wall 1004 and the sixth straight wall 1005, the fifth straight wall 1004, the sixth straight wall 1005, and the first connecting wall 1203 being parallel to each other.

In some embodiments, referring to fig. 2, the third housing 13 has a second flow channel 131, the second flow channel 131 at least partially constituting the second flow chamber 102, the second flow channel 131 opening the second heating element 3 in the thickness direction of the third housing 13, the thickness direction of the third housing 13 being parallel to the thickness direction of the first wall portion 121. The third housing 13 has a second mounting groove 132, and the second mounting groove 132 communicates with the second flow path groove 131. The second heating element 3 is mounted to the second mounting groove 132. The second flow channel groove 131 is provided through the third housing 13, so that the second heating element 3 and the third housing 13 enclose the second flow channel chamber 102. In operation, the medium in the second flow channel cavity 102 is heated by the second heating element 3, and the medium supplies heat for the working condition of the required heat.

Referring to fig. 7 and 8, the first heating plate 21 is welded or adhesively fixed to the first groove bottom surface 3001 of the first mounting groove 1212, and the second heating plate 31 is welded or adhesively fixed to the second groove bottom surface 3002 of the second mounting groove 132. The first flow channel 1211 is concavely disposed on the first bottom surface 3001, and the second flow channel 131 is concavely disposed on the second bottom surface 3001.

With continued reference to fig. 2, the third housing 13 includes a third groove wall 1301, a fourth groove wall 1302 opposite to the third groove wall 1301, a third connecting wall 1303 connecting one end of the third groove wall 1301 and one end of the fourth groove wall 1302, and a fourth connecting wall 1304 connecting the other end of the third groove wall 1301 and the other end of the fourth groove wall 1302, the third groove wall 1301, the fourth groove wall 1302, the third connecting wall 1303, and the fourth connecting wall 1304 being located at the periphery of the second flow passage groove 131. The third groove wall 1301, the fourth groove wall 1302, the third connecting wall 1303, and the fourth connecting wall 1304 together constitute a peripheral wall surface of the second flow channel 131, and the peripheral wall surface of the second mounting groove 132 is located on an outer periphery of the peripheral wall surface of the second flow channel 131. The third connecting wall 1303 and the fourth connecting wall 1304 are flat walls, and the third connecting wall 1303 is parallel to the fourth connecting wall 1304.

In the illustrated embodiment of the application, with continued reference to fig. 2, the third groove wall 1301 includes a third curved wall 130a that projects in a direction toward the fourth groove wall 1302, the third curved wall 130a giving the curved flow path a C-shape. Of course, in other embodiments, as shown in fig. 13, the third groove wall 1301 includes a third curved wall 130a protruding in a direction approaching the fourth groove wall 1302, the fourth groove wall 1302 includes a fourth curved wall 130b protruding in a direction approaching the third groove wall 1301, and the third curved wall 130a and the fourth curved wall 130b give the curved flow path an S shape.

Specifically, referring to fig. 8, the third curved wall 130a includes a third straight wall 2001, a fourth straight wall 2002 parallel to the third straight wall 2001, and a second arc-shaped wall 2003 connecting the third straight wall 2001 and the fourth straight wall 2002, the third straight wall 2001, the fourth straight wall 2002, and the third connecting wall 1303 being parallel to each other.

Referring to fig. 1, the second housing 12 is provided with a first tunnel member 123 and a second tunnel member 124, and the first tunnel member 123 and the second tunnel member 124 are provided on the first peripheral wall 122. The first porthole part 123 has a first porthole 1230 and the second porthole part 124 has a second porthole 1240. Referring to fig. 5 and 6, the housing 1 includes a first passage 103, a second passage 104, and a third passage 105, the first passage 103 communicating the first flow passage chamber 101 with the first duct 1230, the second passage 104 communicating the second flow passage chamber 102 with the second duct 1240, and the third passage 105 communicating the first flow passage chamber 101 with the second flow passage chamber 102.

In the illustrated embodiment of the application, the first channel 1230 is a medium inlet, the second channel 1240 is a medium outlet, and the first channel 103 is provided in the first wall 121. Referring to fig. 5 and 6, the first wall 121 has a first wall passage 1041 and a second wall passage 1051, the third housing 13 has a first housing passage 1042 and a second housing passage 1052, the first housing passage 1042 communicates with the second flow passage chamber 102, the first wall passage 1041 communicates with the first housing passage 1042, and the first wall passage 1041 communicates with the second duct 1240. The first flow channel chamber 101 communicates with the second wall passage 1051, the second wall passage 1051 communicates with the second housing passage 1052, and the second housing passage 1052 communicates with the second flow channel chamber 102, thereby enabling the first flow channel chamber 101 to communicate with the second flow channel chamber 102. The first wall passage 1041 and the first housing passage 1042 together form a second passage 104. The second wall passage 1051 and the second housing passage 1052 together constitute the third passage 105.

Referring to fig. 2 and 4, the first heating element 2 includes a first heating plate 21 and a first connection part 22 connected to the first heating plate 21, the second heating element 3 includes a second heating plate 31 and a second connection part 32 connected to the second heating plate 31, the first heating plate 21 is welded or fixed to the first wall part 121, and the second heating plate 31 is welded or bonded to the third housing 13, which is advantageous in improving the sealability of the first and second flow path chambers 101, 102. Referring to fig. 10, the first heating plate 21 includes first and second surfaces 21a and 21b at opposite sides in a thickness direction thereof, and the second heating plate 31 includes third and fourth surfaces 31a and 31b at opposite sides in the thickness direction thereof. The second surface 21b and the third surface 31a have a first distance H1 therebetween.

With continued reference to fig. 10, the first wall portion 121 includes a first bottom wall 1205, the first bottom wall 1205 is located at the periphery of the first flow channel 1211, the third housing 13 includes a second bottom wall 133, the second bottom wall 133 is located at the periphery of the second flow channel 131, the first bottom wall 1205 is opposite the first surface 21a, and the second bottom wall 133 is opposite the fourth surface 31b. The first bottom wall 1205 has a second distance H2 from the first surface 21a, and the second bottom wall 133 has a third distance H3 from the fourth surface 31b. In the illustrated embodiment of the present application, the second pitch H2 is equal to the third pitch H3, and the first pitch H1 is smaller than the second pitch H2 and the third pitch H3.

Referring to fig. 14 and 15, the first heating element 2 includes a first heating film 23, the second surface 21b is connected to the first heating film 23, the second heating unit 3 includes a second heating film 33, and the third surface 31a is connected to the second heating film 33. The first heating film 23 is disposed opposite to the second heating film 33. Specifically, the first wiring portion 22 is connected to the first heating film 23, and the second wiring portion 32 is connected to the second heating film 33.

Referring to fig. 7, the first wall portion 121 is provided with a first through hole 1213 and a second through hole 1214, and both the first through hole 1213 and the second through hole 1214 communicate with the first chamber 10a. The first wire connection portion 22 is connected to a first cable, which can be connected to the electronic control board 4 through the first through hole 1213, the second wire connection portion 32 is connected to a second cable, and the second cable can be connected to the electronic control board 4 through the second through hole 1214. The first through hole 1213 and the second through hole 1214 each communicate with the first mounting groove 1212.

In the present application, referring to fig. 9, the first heating plate 21 has a first projection S1 on the middle plane M of the electric heater, the second heating plate 31 has a second projection S2 on the middle plane M of the electric heater, the first projection S1 coincides with the second projection S2, and both the first heating plate 21 and the second heating plate 22 are parallel to the middle plane M. That is, the first heating plate 21 and the second heating plate 31 have the same structure, so that one set of heating plate manufacturing mould is reduced, and the cost is reduced.

The electric control board 4 is located between the first housing 11 and the second housing 12, and the first wiring portion 22 and the second wiring portion 32 are electrically connected to the electric control board 4. Referring to fig. 2, the electric heater includes an electrical connector 6, the electrical connector 6 is electrically connected with the electric control board 4, the electrical connector 6 is used for being butted with a butting connector, and the butting connector is connected with a power supply, so that power supply to the electric heater is realized.

In operation, medium sequentially enters the first channel 103 and the first channel cavity 101 from the first channel 1230, the first heating plate 21 heats the medium flowing through the first channel cavity 101, the heated medium enters the second channel cavity 102 through the third channel 103, the second heating plate 21 heats the medium flowing through the second channel cavity 102 again, the heated medium enters the second channel 1240 through the second channel 104, the heated medium flows to the heat-requiring device through the second channel 1240 for heat exchange, the cooled medium enters the first channel 1230 again, and circulation is formed sequentially.

The application also discloses a manufacturing method of the electric heater, which comprises the following steps:

welding or bonding the first heating element 2 and one side wall of the second housing 12 in the thickness direction of the second housing 12, so that a first flow channel cavity 101 is formed between the first heating element 2 and the second housing 12; the second heating element 3 is welded or bonded to the third housing 13 in the thickness direction of the third housing 13 such that a second flow path chamber 102 is formed between the second heating element 3 and the third housing 13, and then the third housing 13 is connected to one side wall of the second housing 12.

Welding the first housing 11 with the other side wall of the second housing 12 before the first heating element 2 is connected to the second housing 12; or alternatively

After the first heating element 2 is connected to the second housing 12, before the second housing 12 is assembled with the third housing 13, the first housing 11 is welded with the other side wall of the second housing 12; or alternatively

After the first heating element 2 is connected to the second housing 12, the first housing 11 is welded to the other side wall of the second housing 12 after the second housing 12 is assembled with the third housing 13.

Specifically, the first heating element 2 is mounted in the first mounting groove 1212 of the second housing 12, both surfaces of the first heating element 2 contacting the second housing 12 are welded or adhesively fixed, and the opening of the first flow channel groove 1211 is sealed by the first heating element 2, thereby forming the first flow channel chamber 101 between the second housing 12 and the first heating element 2. The first heating film 23 of the first heating element 2 is located outside the first flow channel cavity 101.

The second heating element 3 is mounted in the second mounting groove 132 of the third housing 13, both surfaces of the second heating element 3 contacting the third housing 13 are welded or adhesively fixed, and the opening of the second flow channel groove 131 is sealed by the second heating element 3, thereby forming the second flow channel chamber 102 between the third housing 13 and the second heating element 3. The second heating film 33 of the second heating element 3 is located outside the second flow channel chamber 102.

The third casing 13 is fixed to one side of the second casing 12, the seal ring 5 is pressed between the third casing 13 and the second casing 12, the electric control board 4 is mounted in a space enclosed by the first wall portion 121 and the first peripheral wall 122, and the other side of the first casing 11 and the second casing 12 is fixed in a sealing manner, so that a first cavity 10a is formed between the first casing 11 and the second casing 12.

In summary, compared with the prior art, the electric heater of the application has the following advantages:

1. by arranging the first flow channel cavity 101 and the second flow channel cavity 102, the first heating plate 21 carries out primary heating on the medium in the first flow channel cavity 101, the medium flows from the first flow channel cavity 101 to the second flow channel cavity 102, the second heating plate 31 carries out secondary heating on the medium in the second flow channel cavity 102, at least one of the first flow channel cavity 101 and the second flow channel cavity 102 provides a curved flow path for the medium, the flow path of the medium is increased, the heating time is prolonged, the medium can absorb enough heat, and the heating effect is improved.

2. The first heating plate 21 is welded or bonded to the first wall 121, and the second heating plate 31 is welded or bonded to the third housing 13, which is advantageous in improving the sealing properties of the first and second flow path chambers 101 and 102.

3. The first heating plate 21 and the second heating plate 31 are not supported, so that the structure is more compact, the volume is small, and the weight is light.

4. The first heating plate 21 and the second heating plate 31 adopt the same structure, so that a set of heating plate manufacturing molds is reduced, and the cost is reduced.

The above embodiments are only for illustrating the present application and not for limiting the technical solutions described in the present application, and it should be understood that the present application should be based on those skilled in the art, and although the present application has been described in detail with reference to the above embodiments, it should be understood by those skilled in the art that modifications or equivalent substitutions can be made to the present application without departing from the spirit and scope of the present application and modifications thereof should be covered by the scope of the claims of the present application.

Claims

1. An electric heater, characterized by comprising a housing (1), a first heating element (2) and a second heating element (3), at least part of the first heating element (2) and at least part of the second heating element (3) being located within the housing (1);

the shell (1) comprises a first shell (11), a second shell (12) and a third shell (13), wherein the second shell (12) is connected with the first shell (11), the second shell (12) is connected with the third shell (13), and the first shell (11) and the third shell (13) are respectively positioned on different sides of the second shell (12) in the thickness direction of the second shell (12);

the electric heater is provided with a first runner cavity (101) and a second runner cavity (102), the first runner cavity (101) and the second runner cavity (102) can be communicated, the first runner cavity (101) and the second runner cavity (102) are both positioned between the second shell (12) and the third shell (13), and at least one of the first runner cavity (101) and the second runner cavity (102) provides a curved flow path for a medium.

2. The electric heater according to claim 1, characterized in that the second housing (12) comprises a first wall portion (121), the first wall portion (121) having a first flow channel groove (1211), the first flow channel groove (1211) at least partially constituting the first flow channel cavity (101), an opening of the first flow channel groove (1211) in a thickness direction of the first wall portion (121) being directed toward the first heating element (2);

the first wall portion (121) includes a first groove wall (1201), a second groove wall (1202) opposite to the first groove wall (1201), a first connecting wall (1203) connecting one end of the first groove wall (1201) and one end of the second groove wall (1202), and a second connecting wall (1204) connecting the other end of the first groove wall (1201) and the other end of the second groove wall (1202), at least part of the walls of the first groove wall (1201), the second groove wall (1202), the first connecting wall (1203), and the second connecting wall (1204) forming a groove wall of the first flow passage groove (1211);

the first groove wall (1201) comprises a first curved wall (120 a) protruding in a direction approaching the second groove wall (1202), the second groove wall (1202) comprises a second curved wall (120 b) protruding in a direction approaching the first groove wall (1201), the first curved wall (120 a) and the second curved wall (120 b) give the curved flow path an S shape; alternatively, the first groove wall (1201) includes a first curved wall (120 a) protruding in a direction approaching the second groove wall (1202), the first curved wall (120 a) giving the curved flow path a C-shape.

3. An electric heater according to claim 1, characterized in that the third housing (13) has a second flow channel groove (131), the second flow channel groove (131) at least partly constituting the second flow channel cavity (102), the opening of the second flow channel groove (131) in the thickness direction of the third housing (13) being directed towards the second heating element (3);

the third housing (13) includes a third groove wall (1301), a fourth groove wall (1302) opposite to the third groove wall (1301), a third connecting wall (1303) connecting one end of the third groove wall (1301) and one end of the fourth groove wall (1302), and a fourth connecting wall (1304) connecting the other end of the third groove wall (1301) and the other end of the fourth groove wall (1302), at least part of the walls of the third groove wall (1301), the fourth groove wall (1302), the third connecting wall (1303), and the fourth connecting wall (1304) forming the groove wall of the second flow passage groove (131);

the third groove wall (1301) includes a third curved wall (130 a) protruding in a direction approaching the fourth groove wall (1302), the third curved wall (130 a) giving the curved flow path a C-shape; alternatively, the third groove wall (1301) includes a third curved wall (130 a) protruding in a direction approaching the fourth groove wall (1302), the fourth groove wall (1302) includes a fourth curved wall (130 b) protruding in a direction approaching the third groove wall (1301), and the third curved wall (130 a) and the fourth curved wall (130 b) give the curved flow path an S shape.

4. An electric heater according to claim 2 or 3, characterized in that the first heating element (2) comprises a first heating plate (21), the second heating element (3) comprises a second heating plate (31), the first heating plate (21) being welded or adhesively secured to the first wall portion (121), the second heating plate (31) being welded or adhesively secured to the third housing (13).

5. The electric heater according to claim 4, wherein the first wall portion (121) has a first mounting groove (1212), the first heating element (2) is mounted to the first mounting groove (1212), the third housing (13) has a second mounting groove (132), and the second heating element (3) is mounted to the second mounting groove (132);

the first heating plate (21) is welded or bonded and fixed with a first groove bottom surface (3001) of the first mounting groove (1212), and the second heating plate (31) is welded or bonded and fixed with a second groove bottom surface (3002) of the second mounting groove (132);

the first runner groove (1211) is concavely arranged on the first groove bottom surface (3001), and the second runner groove (131) is concavely arranged on the second groove bottom surface (3002).

6. An electric heater as claimed in claim 4, wherein the first heating plate (21) includes first and second surfaces (21 a, 21 b) on opposite sides in a thickness direction thereof, and the second heating plate (31) includes third and fourth surfaces (31 a, 31 b) on opposite sides in the thickness direction thereof;

the first wall portion (121) includes a first bottom wall (1205), the first bottom wall (1205) is located at a periphery of the first flow channel (1211), the third housing (13) includes a second bottom wall (133), the second bottom wall (133) is located at a periphery of the second flow channel (131), the first bottom wall (1205) is opposite to the first surface (21 a), and the second bottom wall (133) is opposite to the fourth surface (31 b);

the second surface (21 b) and the third surface (31 a) have a first pitch (H1), the first bottom wall (1205) and the first surface (21 a) have a second pitch (H2), the second bottom wall (133) and the fourth surface (31 b) have a third pitch (H3), and the first pitch (H1) is smaller than the second pitch (H2) and the third pitch (H3).

7. An electric heater according to claim 6, characterized in that the first heating element (2) comprises a first heating film (23), the second surface (21 b) is connected to the first heating film (23), the second heating unit (3) comprises a second heating film (33), and the third surface (31 a) is connected to the second heating film (33).

8. An electric heater according to claim 7, characterized in that the first heating element (2) comprises a first wiring portion (22) connected to the first heating film (23), the second heating element (3) comprises a second wiring portion (32) connected to the second heating film (33);

the electric heater comprises an electric control plate (4), wherein the electric control plate (4) is positioned between the first shell (11) and the second shell (12), and the first wiring part (22) and the second wiring part (32) are electrically connected with the electric control plate (4).

9. The electric heater according to claim 1, wherein the second housing (12) is provided with a first tunnel part (123) and a second tunnel part (124), the first tunnel part (123) having a first tunnel (1230), the second tunnel part (124) having a second tunnel (1240), the housing (1) comprising a first channel (103), a second channel (104) and a third channel (105), the first channel (103) communicating the first channel cavity (101) with the first tunnel (1230), the second channel (104) communicating the second channel cavity (102) with the second tunnel (1240), the third channel (105) communicating the first channel cavity (101) with the second channel cavity (102).

10. An electric heater as claimed in claim 1, characterised in that it comprises a sealing ring (5), the sealing ring (5) being located between the second housing (12) and the third housing (13).