Electric heater

Abstract

An electric heater for an automobile vehicle, with an electric heating element, which is connectable to an electric power source, with an insulating element and with a tube with the electric heating element being placed inside the tube and being electrically insulated from the tube, with the tube having at least one opening through which the insulating element and the electric heating element can be inserted into the tube. The electric heater features a safety element, which is plugged into the at least one opening of the tube, with the safety element having at least one distance element, which defines the orientation of the electric heating element and/or the insulating element in relation to the tube. Furthermore the invention relates to a heat exchanger with at least one electric heater.

Claims

1. An electric heater for an automobile vehicle, the electric heater comprising: an electric heating element that is connectable to an electric power source; an insulating element; a tube, the electric heating element being placed inside the tube and being electrically insulated from the tube, the tube having at least one opening through which the insulating element and the electric heating element are inserted into the tube; and a safety element that is plugged into the at least one opening of the tube, the safety element having at least one distance element, which defines an orientation of the electric heating element or the insulating element in relation to the tube, wherein the distance element creates a defined distance between the inner wall of the tube and the insulating element.

2. The electric heater as claimed in claim 1, wherein the distance element creates a defined distance between the inner wall of the tube and the electric heating element.

3. The electric heater as claimed in claim 2, wherein the defined distance is an air gap between the insulating element and/or the heating element and the inner wall of the tube.

4. The electric heater as claimed in claim 1, wherein the distance element protrudes in a rectangular direction from a base of the safety element.

5. The electric heater as claimed in claim 1, wherein the safety element has a boundary area, which protrudes in a rectangular direction from the base.

6. The electric heater as claimed in claim 1, wherein the distance element limits the movement of the electric heating element and/or the insulating element relative to the tube in a longitudinal direction and/or in a rotational direction.

7. The electric heater as claimed in claim 1, further comprising a cavity between a base of the safety element and the insulating element.

8. An electric heater for an automobile vehicle, the electric heater comprising: an electric heating element that is connectable to an electric power source; an insulating element; a tube, the electric heating element being placed inside the tube and being electrically insulated from the tube, the tube having at least one opening through which the insulating element and the electric heating element are inserted into the tube; and a safety element that is plugged into the at least one opening of the tube, the safety element having at least one distance element, which defines an orientation of the electric heating element or the insulating element in relation to the tube, wherein the safety element has an at least partially circumferential groove in which the wall of the tube is received.

9. The electric heater as claimed in claim 8, wherein the safety element has a boundary area, which protrudes in a rectangular direction from the base, and wherein the boundary area and/or the distance element features at least one rib element, which faces into the groove.

10. An electric heater for an automobile vehicle, the electric heater comprising: an electric heating element that is connectable to an electric power source; an insulating element; a tube, the electric heating element being placed inside the tube and being electrically insulated from the tube, the tube having at least one opening through which the insulating element and the electric heating element are inserted into the tube; and a safety element that is plugged into the at least one opening of the tube, the safety element having at least one distance element, which defines an orientation of the electric heating element or the insulating element in relation to the tube, wherein the safety element has two distance elements protruding in a rectangular direction from a base of the safety element with each of the distance elements having a recess to receive the electric heating element and/or the insulating element.

11. The electric heater as claimed in claim 10, wherein the distance elements and/or the base are made out of a material, which is inflexible enough to avoid relative movement between the tube and the insulating element and/or the electric heating element.

12. The electric heater as claimed in claim 10, wherein the distance elements are set apart from the inner wall of the tube such that an air gap is created between the distance elements and the inner wall of the tube.

13. A heat exchanger with at least one electric heater, the electric heater comprising: an electric heating element that is connectable to an electric power source; an insulating element; a tube, the electric heating element being placed inside the tube and being electrically insulated from the tube, the tube having at least one opening through which the insulating element and the electric heating element are inserted into the tube; and a safety element that is plugged into the at least one opening of the tube, the safety element having at least one distance element, which defines an orientation of the electric heating element or the insulating element in relation to the tube, wherein the heat exchanger comprises: a plurality of fluid-tubes, which are spaced apart from each other, the fluid-tubes and electric heaters being arranged in an alternating order, and a plurality of heat transmitting fins being arranged between the fluid-tubes and the electric heaters, wherein a first fluid flows through the fluid-tubes and a second fluid flows around the fluid-tubes and the electric heaters.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus, are not limitive of the present invention, and wherein:

(2) FIG. 1 shows a perspective view of one end section of a tube of a heat exchanger where an electric heating element, which is encased by two ceramic insulating elements, is integrated into the tube, with the tube having a safety element plugged into the opening of the tube to position the electric heating element and the insulating element relative to the inner wall of tube;

(3) FIG. 2 shows a cross-sectional view of the tube according to FIG. 1 where the insulating element is recessed into the distance elements of the safety element with the safety element having a circumferential boundary area, which encases the outer wall of end section of the tube, and

(4) FIG. 3 shows an embodiment of the safety element, which is plugged into the opening of a tube as shown in FIG. 2.

DETAILED DESCRIPTION

(5) FIG. 1 shows the end section of a tube 1, where the tube 1 is a flat tube 1, which features two broadsides that are arranged parallel to each other and two narrow sides that are also arranged parallel to each other. The narrow sides thereby connect the broadsides to form the tube 1. The tube 1 can be built out of only one element or can consist of several elements, which can be connected with each other to form the tube. In an advantageous embodiment the tube is made out of a material, which has a good thermal conductivity.

(6) Inside of the tube is an electric heating element 4, which is arranged between two insulating elements 5. The electric heating element 4 is connected to a positive pole and a negative pole of a power source. The power source is not shown in FIG. 1.

(7) The electric heating element 4 and the insulating elements 5 can be press-fitted together. In other preferred embodiments further fixation means, such as glue, can be used to connect the electric heating element 4 to the insulating elements 5. The insulating elements 5 can be arranged within the tube 1 in a way that an air gap is created between the insulating elements 5 and the inner wall of the tube 1. In a preferred embodiment the air gap is created between the narrow sides of the tube 1 and the insulating elements 5, whereas the broadsides of the tube 1 are press-fitted to the insulating elements 5.

(8) The FIG. 1 furthermore shows a safety element 2, which is plugged in the downwards facing opening of the tube 1. The safety element 2 encases the tube 1 thereby at least partially with a boundary area 6. The safety element 2 furthermore features a circumferential flange 3, which protrudes in a direction that is rectangular to the boundary area 6 and facing outwards. The flange 3 can be used to create defined distances between tubes 1 that are arranged adjacent to each other.

(9) In an embodiment the safety element 2 is made out of a non-conductive and/or elastic material. The non-conductive material helps to create an insulation. Furthermore the elastic properties of the material makes the assembly of the safety element 2 on the tube 1 easier.

(10) The safety element 2 features a recess, in which the tube 1 can be inserted. The recess is formed between the boundary area 6, which protrudes in a rectangular direction from the flat base of the safety element 2, and the distance elements 8, which protrudes in a direction parallel to the boundary area 6 from the base of the safety element 2.

(11) FIG. 2 shows a cross-sectional view of the tube 1, which is already shown in FIG. 1. The cut runs parallel to the broadsides of the tube 1 and cuts through the middle axis of the tube 1.

(12) In FIG. 2 it can be seen, that the electric heating elements 4 are placed within a frame, which is then covered by the insulating elements 5. The electric heating element 4 can be fitted into the recesses free from backlash, so that no relative movement is possible. Alternatively an air gap 12 can be formed between the electric heating element 4 and the surrounding frame.

(13) As can be seen in FIG. 2, the insulating elements 5 are spaced apart from the inner wall of the narrow sides of the tube 1 in a way that an air gap 11 is created between the inner wall and the insulating elements 5.

(14) In the embodiment shown in FIG. 2 the electric heating element 4 is encased by the insulating elements 5 only in the direction of the broadsides of the tube 1 but not in the direction of the narrow sides of the tube. Along the direction of the narrow sides, the electric heating element 4 might at least be partially encased by the insulating elements 5. Relative movement between the electric heating element 4 and the insulating elements 5 can therefore lead to a direct contact between the electric heating element 4 and the inner wall of the tube 1, which may cause an electric short circuit and thus might be electrifying the tube 1.

(15) The safety element 2 features a base 13 from which the boundary area 6 protrudes in a rectangular direction. Furthermore two distance elements 8 protrude from the base 13 in the same direction parallel to the boundary area 6. Between the distance elements 8 and the boundary area 6 a groove 14 is built, in which the tube 1 or more specific the wall of the tube 1, can be inserted. While the insertion of the tube 1 into the groove 14, the distance elements 8 are inserted into the tube 1 while the boundary area 6 encases the outer walls of the tube 1.

(16) The boundary area 6 features at least partially circumferential rib elements 7, which protrude from the boundary area 6 into the groove 14. These rib elements 7 are in direct contact with the outer wall of the tube 1. The rib elements 7 can thereby be elastic in such a way, that they are compressed while the insertion of the tube 1, so that a pressure on the outer wall of the tube 1 is created, which leads to a better fixation of the tube 1 in the safety element 2.

(17) In an alternative embodiment the tube can show a number of creases on the outer wall, which correspond with the rib elements in such a way that the rib elements are inserted into the creases while the insertion of the tube. This will create a form closure between the safety element and the tube and thus improves the connection.

(18) The distance elements 8 each have a c-shaped recess into which the insulating elements 5 are inserted and thus fixated. Each of the c-shaped recesses thereby encases especially the narrow side of the insulating elements 5 with its base section and each of the broadsides at least partially with the free flanks of the c-shaped recess. Bedstops are positioned within the recesses, which limit the way of travel of the insulating elements 5 into the recesses. The insulating elements 5 are predominantly encased by the distance elements 8 at the narrow sides of the tube 1. In an alternative embodiment the two distance elements can be built as one single distance element, which encases the complete end section of the insulating elements 5. The outwards facing sides of the distance element and the inwards facing sides of the boundary area 6 thereby form the groove into which the wall of the tube can be inserted.

(19) The distance elements 8 furthermore feature one ledge 9, which creates a defined distance between the distance elements 8 and the inner wall of the tube 1. The ledge 9 thereby helps to avoid direct contact between the insulating elements 5 and/or the electric heating element 4 and the inner wall of the tube 1.

(20) In an alternative embodiment, the distance elements do not cover the electric heating element in the direction of the broadsides and/or in the direction of the narrow sides. This is especially beneficial, as the heat transmission in these directions is not negatively influenced by the material of the safety element. Usually the main portion of the heat is transferred via the broadsides of the tube.

(21) In FIG. 2 the insulating elements 5 possess a cavity 10 between the base 13 and the insulating elements 5. In an alternative embodiment the base can feature a further ledge, which can be inserted into the cavity, to further fixate the insulating elements against the safety element.

(22) FIG. 3 shows an alternative embodiment of the safety element 2, which is already shown in FIG. 2. The safety element 2a of FIG. 3 features two distance elements 8a, which protrude from the base 13 of the safety element 2a. As a modification from the distance elements 8 from FIG. 2 the distance elements 8a do not possess the ledges 9. Therefore the distance elements 8a have no direct contact with the inner wall of the tube 1. Even without theses ledges 9 the distance elements 8a create an air gap 11 between the insulating element 5a and the tube 1, which is necessary to avoid electric short circuits between the tube 1 and the insulating element 5a and/or the electric heating element 4, which is arranged within the insulating element 5a.

(23) In an embodiment the distance elements 8a and/or the base 13 of the safety element 2a are made of a material, which is inflexible enough to give enough stability to the insulating element 5a in order to avoid relative movement of the insulating element 5a and the distance element 8a relative to the tube 1. But even if the distance elements 8a would allow enough movement of the insulating element 5a, the material of the distance elements 8a, which encases the insulating element 5a, would act as an insulation between the insulating element 5a and the inner wall of the tube 1.

(24) As already described in FIG. 2 the insulating element 5a is encased by the distance elements 8a on the narrow sides of the tube 1, so that in case of a relative movement the distance elements 8a would come into direct contact with the inner wall of the tube 1 instead of the insulating element 5a or the electric heating element 4.

(25) A further modification shown in FIG. 3 is that the boundary area 6 shows no rib elements protruding from the boundary area 6 in the direction of the center of the tube 1. The fixation between the outer surface of the tube 1 and the inner surface of the boundary area 6 is formed by a friction bond, rather than by a form closure as shown in FIG. 2.

(26) Furthermore the insulating element 5a does not feature a cavity like the cavity 10 that is shown in FIG. 2. The down-facing part of the insulating element 5a rests against the inner surface of the base 13 of the safety element 2a. The increased contact area between the insulating element 5a and the safety element 2a leads to a higher stability of the connection between the safety element 2a and the insulating element 5a.

(27) The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are to be included within the scope of the following claims.