WO2018052366A1

WO2018052366A1 - Heat exchanger and method for manufacturing such a heat exchanger

Info

Publication number: WO2018052366A1
Application number: PCT/SE2017/050905
Authority: WO
Inventors: Stefan BREDELL; Arne Moberg; Peter Kjaerboe
Original assignee: Bredell Stefan; Arne Moberg; Peter Kjaerboe
Priority date: 2016-09-16
Filing date: 2017-09-14
Publication date: 2018-03-22
Also published as: SE1651235A1; SE540208C2

Abstract

The present invention relates to a heat exchanger and a method for manufacturing such a heat exchanger. The heat exchanger comprises a material body (3) comprises a plurality of projecting end portions (3a, 3b) which comprises outer end surfaces(la, lb, 2a, 2b) defining an end of the material body (3) and spaces (6, 7) which are arranged between adjacent end portions (3a, 3b) which spaces (6, 7) are defined by an inner end surface (la, lb, 2a, 2b) which is located at a distance from the end of the material body. Said outer end surfaces (la, lb, 2a, 2b) comprises openings of channels (lc, 2c) which direct a first medium (4) through the material body (3) and said inner end surfaces (la, lb, 2a, 2b) comprises openings of channels (lc, 2c) which direct a second medium (5) through the material body (3). The heat exchanger comprises a clamping device (11, 15) which is adapted to press together the projecting end portions (3a, 3b) such that a tight connection is provided between adjacent end portions (3a, 3b) at an end of the material body (3).

Description

Heat exchanger and method for manufacturing such a heat exchanger BACKGROUND OF THE INVENTION AND PRIOR ART

The present invention relates to a heat exchanger and a method for manufacturing such a heat exchanger according to the preambles of claims 1 and 14. In houses with supply and exhaust ventilation, it is possible to preheat the air which is directed into the house by means of the air which is directed out of the house. Similarly, it is possible to cool the air before it is directed into the house when it is warmer outside than inside. In a ventilation duct with counter flow heat exchanger, the air directed into the house can obtain substantially the same temperature as the air directed out of the house. In this way, the heating cost for the house can be radically reduced in winter and analogously for comfort cooling in summer in a very easy way. However, conventional counter flow heat exchangers have a relatively complicated structure and a therefore relatively expensive to procure. Furthermore, they may require a relatively large internal mounting space in the house.

SE 1150385-1 shows a heat exchanger comprising a set of first channel elements directing a first medium through the heat exchanger and a set of second channel elements directing a second medium through the heat exchanger. The first channel elements and the second channel elements are alternately stacked on each other. The one ends of the first channel elements are arranged in a common plane defining an end surface of the heat exchanger where the first medium is directed out. The corresponding ends of the second channel elements are arranged in a plane at a distance from the end surface of the heat exchanger. The heat exchanger comprises stop elements between each end of the first plate-shaped channel element which prevent the second medium to be directed out via the end surface of the heart exchanger. In case the heat exchanger comprises a large number of such channel elements it requires a correspondingly large number of stop elements to be applied and fixed to the heat exchanger between the ends of each channel element. The application of the stop elements complicates the production of the heat exchanger considerably.

SUMMARY OF THE INVENTION

The object of the present invention is to provide a heat exchanger having a simple structure, requiring a relatively small space and can be manufactured to a low cost.

This object is achieved by the heat exchanger of the initially mentioned kind, which is characterized by the features defined in the characterizing portion of claim 1. Thus, the heat exchanger comprises a clamping device which is adapted to press together the individual end portions in connection to adjacent the end of the material body such that a tight connection is established between the end portions. Advantageously, the end portions have the property that they are easy to deform elastically and/or plastically such that they can be pressed together with a relatively small force and create said tight connection. Advantageously, the material body consists of a plastic material with suitable properties. The costs for manufacturing such a material body is low. Alternatively, the material body may be manufactured by a material such as, for example, aluminum.

The clamping device may be a band element or the like which is applied and tightened by means of, for example, a tying machine around the end of the material body. Alternatively, the clamping may be a tape which manually or by machine is wrapped around the end of the material body. According to a further alternative, the clamping device may comprise two plate-shaped clamping elements which are screwed together from opposite sides of the heat exchanger. The clamping device may thus be designed in many different ways. Since the end portions a pressed together against each other, no stop elements need to be arranged between each of the end portions at the end of the material body. The number of components in the heat exchanger may be considerably reduced since no stop element need to be applied between each of the end portions. By means of the clamping device, the manufacturing process of heat exchanger is significantly simplified. Thus, the heat exchanger can be manufactured to a low cost. According to an embodiment of the present invention, the clamping device comprises at least one clamping body. Advantageously, the clamping body has a volume such that it fills out the empty space which is created when the end portions are pressed together. By means of such a clamping body, the material body maintains it original volume at the end. Thereby, the mounting of the heat exchanger inside, for example, an air duct or a casing is facilitated.

According to an embodiment of the present invention, the clamping device comprises a clamping body adapted to be applied in a space between two centrally arranged end portions. In this case, half of the end portions are pressed together on one side of the clamping body and the other half of the end portions on the opposite side of the clamping body. According to an embodiment of the present invention, the clamping device comprises two clamping bodies which are adapted to be arranged externally of the two outermost located end portions. In this case, all end portions are pressed together against the middle by the two clamping bodies such that the openings of the end portions are positioned in a center area between the two clamping bodies.

According to an embodiment of the present invention, the clamping body is designed such that it presses together the end portions in connection with its entry into a space between two adjacent end portions. In this case, the clamping body may be wedge- shaped such that it transmits a pressing force on the end portions. The clamping body may also comprise a suitable shaped surface giving the end portions a suitable curved shape adjacent to the end of the material body.

According to an embodiment of the present invention, said outer end surfaces are arranged in a common first plane and said inner end surfaces are arranged in a second common plane. In this case, spaces of the same size are provided between adjacent end portions. The common second plane may be parallel to the first plane. Alternatively, the second plane may have an angle relative to the first plane. According to an embodiment of the present invention, the material body is made of first channel elements and second channel elements which are alternately stacked on each other. Advantageously, the first channel elements and the second channel elements may have an identical design. The including channel elements may be manufactured of relatively light and inexpensive materials such as plastic materials. Certain plastic materials have excellent heat transfer properties. The channel elements may be provided with relatively thin walls in order to increase the heat transfer properties of the heat exchanger. Advantageously, the channel elements are manufactured by extrusion. Advantageously, the channel elements comprise straight channels for the respective mediums which extend between the openings in the end surfaces of the channel elements. The flow losses in such channels are small. The first channel elements and the second channel elements may be of different length. In the case the first channel elements is longer than the second channel elements, the ends of the first channel elements constitute the end portions of the material body. In this case, a first clamping device is advantageously used for pressing together the end portions of the first channel elements at an end and a second clamping device the end portions of the first channel elements at an opposite second end. Alternatively, the first channel elements and the second channel elements may be of the same length. In this case, the end surfaces of the first channel elements may be arranged in a common plane which constitute a first end of the material body while the end surfaces of the second channel elements are arranged in a common plane which constitutes a second end of the material body. In this case, a clamping device is advantageously used for pressing together the end portions of the first channel elements at the first end and a second clamping device for pressing together the second channel elements at the second end.

According to an embodiment of the present invention, the material body is manufactured as a coherent unit. Such a material body is advantageously manufactured by extrusion. With this manufacturing process, elongated material bodies can be formed with a constant cross section shape. In this case, a material body is thus obtained in a single piece which comprises the first channels and the second channels. After extrusion, the first channels has openings in one plane and the second channels has openings in another plane. In order to remove material and create projecting end portions with intermediate spaces, a suitable tool such as a milling machine, a saw or the like can be used.

According to an embodiment of the present invention, the heat exchanger comprises a casing which encloses the material body. The casing may comprise at least one inlet directing one of said mediums, via a side opening, into said spaces. Such an inlet ought to be dimensioned such that the medium is distributed substantially uniformly between the different spaces. The casing may comprise at least one outlet to receive one of said mediums, via a side opening, from said spaces. Such an outlet ought to be dimensioned such that it receives the medium substantially uniformly from the different spaces. The casing may comprise a wall surface adapted to cover the side openings to said spaces on one side of the material body. Thereby, the side openings on the opposite side may be used to direct a medium to or out from the spaces. The initially mentioned object is also achieved with the method according to claims 14 and 15.

BRIEF DESCRIPTION OF THE DRAWINGS In the following, preferred embodiments of the invention are described as examples with reference to the attached drawings, on which:

Fig. 1 shows channel elements for manufacturing of a material body according to the present invention,

Fig. 2 shows alternative channel elements for manufacturing of a material body according to the present invention,

Fig. 3 shows a heat exchanger according to a first embodiment of the invention,

Fig. 4 shows the casing of the heat exchanger in Fig. 3,

Fig. 5 shows a heat exchanger according to a second embodiment of the invention,

Fig. 6 shows the casing of the heat exchanger in Fig. 5,

Fig. 7 shows a heat exchanger according to a third embodiment of the invention, Fig. 8 shows the casing of the heat exchanger in Fig. 7,

Fig. 9 shows an end of a fourth embodiment of the heat exchanger and

Fig. 10 shows an end of a fifth embodiment of the heat exchanger. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE PRESENT INVENTION

Fig. 1 shows first channel elements 1 and second channel elements 2 which are alternately stacked on each other. The first channel elements 1 and the second channel elements 2 form in a connected state a material body 3 which comprises a plurality of first end portions 3 a which are arranged at a first end of the material body 3 and a plurality of second end portions 3b which are arranged at a second end of the material body 3. The first channel elements 1 have a straight extension between a first end surface la and a second end surface lb. The first channel elements 1 comprise first channels lc with openings in the first end surface la and in the second end surface lb. The first channels lc are adapted to direct a first medium 4. The second channel elements 2 have a straight extension between a first end surface 2a and a second end surface 2b. The second channel elements 2 comprise second channels 2c with openings in the first end surface 2a and in the second end surface 2b. The second channels 2c are adapted to direct a second medium 5. The first channel elements 1 and the second channel elements 2 have a constant cross section shape in a longitudinal direction. Thus, they can with advantage be manufactured by extrusion. Extruded products can many times be manufactured to a low cost. The channel elements 1, 2 can, for example, be manufactured of a plastic material. Advantageously, they can be performed by so-called twin-wall plastic sheets which are used as wall material in green houses or in packaging. Another inexpensive material which can be used such as channel elements is treated corrugated cardboard. Alternatively, the channel elements 1, 2 can be manufactured of a more expensive material such as suitable metal materials with excellent heat transfer properties.

In this case, the first channel elements 1 comprise the first end portions 3 a. The first end surfaces of the first channel elements 1 are arranged in a plane Ai which defines a first end of the material body 3. The first channel elements 1 comprise in this case also the second end portions 3b of the material body. The second end surfaces of the first channel elements lb are arranged in a plane Bi which defines a second end of the material body 3. The first channel elements 1 have, in this case, a length corresponding to the length of the material body 3. The second channel elements 2 are, in this case, shorter than the first channel elements 1. The first end surfaces 2a of the second channel elements are located in a plane A₂ which is arranged at a distance from the plane Ai and thus at a distance from a first end of the material body 3. The second end surfaces 2b of the second channel elements 2 are arranged in a plane B₂ which is arranged at a distance from the plane Bi and thus at a distance from the second end surface of the material body 3.

Since the second channel elements 2 do not extend all the way to the first end of the material body 3, a space 6 is obtained outside each first end surfaces 2a of the second channel elements. The first spaces 6 is upwardly and downwardly limited by adjacent projecting first end portions 3b of the first channel elements 1. On the other hand, the first spaces 6 have no lateral limitations at the first end of the material body 3 in the first plane Ai. Thus, each of the first spaces 6 has two side openings 6a and one end opening 6b adjacent to the first end of the material body 3. Since the second channel elements 2 do not either extend all the way to the second end of the material body 3 in the plane Bi a corresponding second space is provided outside each of the second end surfaces 2b of the second channel elements 2. The second spaces 7 are upwardly and downwardly limited by projecting end portions of the first channel elements 1. The second spaces 7 have either no lateral limitations and at the second end of the material body 3 in the plane Bi. Thus, each of the second spaces 7 has two side openings 7a and one end opening 7b adjacent to the second end of the material body 3.

In this case, the first medium 4 is directed into the first channels lc via the openings in the first end surface la which are arranged in the plane Ai. The first medium 4 is directed out from the first channels lc via openings in the second end surface lb which are arranged in the plane Bi. The second medium 5 is received in the second spaces 7 and is directed into the second channels 2c at the second end surfaces of the second channel elements 2b in the plane B₂. The second medium 5 is directed out from the second channels 2c via the openings in the first end surface2a which are located in the plane A₂ and is received in the first spaces 6 before it leaves the material body 3. Fig. 2 shows an alternative material body 3 which comprises first channel elements 1 and second channel elements 2 of the same length. In this case, the first channel elements 1 have first end surfaces la which are arranged in the plane A₂ and second end surfaces lb which are arranged in the plane Bi which is located at a distance from the second end of the material body 3 in the plane B₂. The second channel elements 2 have first end surfaces 2a in the plane Ai. The second channel elements 2 have second end surfaces 2b which are arranged in the plane B₂. In this case, first spaces 6 are obtained on the outside of the first end surfaces of the first channel elements la adjacent to the first end of the material body 3 and second spaces 7 on the outside of the second end surfaces of the second channel elements 2b adjacent to the second end of the material body 3.

In this case, the first medium 4 is directed into the first spaces 6. Thereafter, the first medium 4 is directed into the first channels lc of the first channel elements 1. The first medium 4 leaves the first channels lc at the second end of the material body 3 in the plane Bi. The second medium 5 is directed into the second spaces 7. Thereafter, the second medium 5 is directed into the second channels 2c of the second channel elements 2. The second medium 5 leaves the second channels 2c at the first end of the material body 3 in the plane Ai. Alternatively to first and second channel elements which are stacked on each other, the material body 3 can be manufactured in one piece as a homogenous unit

Fig. 3 shows an embodiment of a heat exchanger which comprises the material body in Fig. 2. The heat exchanger comprises except the material body 3 a casing 8 which encloses the material body 3. In this case, the casing 8 also comprises a heat insulating material 9. The individual first channel elements 1 and the second channel elements 2 are manufactured of a material such that it is possible with a relatively small force to press together the end portions of the material body 3a, 3b. When that occurs, a tight connection can be provided between the end portions 3 a at the first end of the material body 3 and between the end portions 3b at the second end of the material body 3. A clamping device in the form of at least one wedge-shaped clamping body 11 is pushed into a space 6 between two centrally arranged first end portions 3 a at the first end of the material body. The clamping body 11 has two sloping side surfaces. The clamping body 11 is dimensioned such that the dimensions of the material body 3 is not changed when it reaches a mounting position in which it creates a tight seal between the end portions 3a the first end of the material body. A corresponding clamping body 11 is applied at the second end of the material body where it is pushed in in a corresponding manner such that it creates a tight seal between the second end portions 3b.

Fig. 4 shows the casing 8 in Fig. 3 in a transverse plane. The first channel elements 1 have first end surfaces la in a plane A₂ which slopes in relation to a longitudinal axis 12 through the material body 3. First spaces 6 are created between the first end surfaces of the first channel elements la in the plane A₂ and the first end surfaces 2a of the second channel elements 2 in the plane Ai. The second channel elements 2 have second end surfaces 2b in a plane B₂ which slopes in relation to the longitudinal axis 12 through the material body 3. Second spaces 7 are created between the second end surfaces of the second channel elements 2b in the plane B₂ and the end surfaces in the first channel elements in the plane Bi . The casing 8 comprises an inlet 8a for the first medium adjacent to the first end of the material body 3. Thus, the first medium 4 can be led, via the side openings 6a, into the first spaces 6. The casing 8 comprises a second inlet 8b for the second medium 5 adjacent to the second end of the material body 3. Thus, the second medium 5 can be directed, via the side openings 7a, into the second spaces 7. The casing 8 comprises no openings on an opposite second side to the inlet 8a, 8b. Thus, the casing 8 covers the side openings 6a, 7a which are arranged on this second side of the material body 3.

During operation, the first medium 4 is directed into the heat exchanger, via the first inlet 8a and the side opening 6a at the first side of the material body, to the first spaces 6 at the first end of the material body. Since the clamping body 11 has sealed the first spaces 6 in the plane Ai and the side opening 6a of the casing 8 at the second side of the material body 3, the first medium can only be directed into the first channels lc via the openings in the first end surfaces lb which are arranged in the plane A₂. Thereafter, the first medium 4 is directed along the first channels lc until it is directed out via openings in the second end surface lb in the plane Bi. The second medium 5 is directed into the heat exchanger, via the second inlet 8b, to the second spaces 7 adjacent to the second end of the material body 3. Since the clamping body 11 has sealed the second spaces 7 in the plane Bi and the casing 8 the side opening 7a at the second side of the material body 3, the second medium can only be directed into the second channels 2c via the openings in the second end surface 2b which are arranged in the plane B₂. Thereafter, the second medium 5 is directed along the second channels 2c and out via openings in the first end surface 2a which are arranged in the plane Ai. In this case, the heat exchanger constitutes a counter flow heat exchanger in the area between the planes A₂- B₂ where a heat transfer is provided between the first the medium and the second medium when they are directed in an opposite direction through the first channels 1 and the second channels 2. Heat transfer is also provided between the mediums 6, 7 when they are in the first spaces 6 in the area between Ai-A₂ and the second spaces 7 and in the areas between Bi-B₂. In these areas, the heat exchanger can be defined as a cross- flow heat exchanger.

Fig. 5 and 6 show an alternative embodiment of the heat exchanger. In this case, two clamping bodies 11 are applied at the first end of the material body 3 and two clamping bodies 11 at the second end of the material body 3. The clamping body 11 is applied between the casing 8 and outermost located end portions 3 a, 3b. In this case, the clamping body 11 has a surface which is parallel to the casing 8 and an inclined surface which is in contact with the outermost located end portion 3a, 3b. When the clamping bodies 11 is pushed into the spaces between the casing 8 and the outermost located end portions 3a, 3b, the end portions 3a, 3b are successively pressed together until they come in contact with each other and create a sealed connection at the ends of the material body. In this case, a uniform central outlet flow of the first the medium 4 is obtained at the first end of the material body 3 and a uniform central outlet flow of the second medium 5 at the second end of the material body 3. The clamping bodies 11 are dimensioned such that they occupy and seals the end openings 6b of the first spaces 6 and the end openings 7b of the second spaces 7. Fig. 7 and 8 shows a further alternative embodiment of the heat exchanger. In this case, the casing 8 has a first inlet 8 a for the first the medium 4 on one side and a second inlet for the second medium 5 on an opposite side. The casing 8 has walls which seals the side openings 6a of the first space 6 and the side openings 7a of the second space 7 on opposite sides of said inlets 8a, 8b. The casing 8 comprises, at the front end of the material body 3, a chamber 13 which receives the second medium 5 leaving the first end of the material body 3. The casing 8 comprises an outlet 8c directing out the second medium 5 from the chamber 13.

Fig. 9 shows an alternative clamping device which both comprises a clamping body 11 and a band element 15 which hold together the end portions 3a and the clamping body 11 in a tight position. The band element 15 can be applied by means of, for example, a tying machine. Fig. 10 shows a clamping device which only comprises a band element 15 or a tape which hold together the end portions 3a in a tight position. In this case, the material body 3 obtains a smaller dimension at the first end.

The present invention is not restricted to the embodiments in the above mentioned drawings but may be varied freely within the scoop of the claims. In the described embodiments, the two mediums are directed in opposite directions through the heat exchanger. However, it is possible to arrange the inlets for both mediums and the outlets for both mediums at the same end of the heat exchanger such that the mediums are directed in the same direction through the heat exchanger. In this case, a co-current heat exchanger is obtained. The heat exchanger can be used to transfer heat between two substantially arbitrary first and second mediums. Mediums may be gaseous or liquid.

Claims

1. A heat exchanger comprising a material body (3) which comprises a plurality of projecting end portions (3a, 3b) comprising outer end surfaces (la, lb, 2a, 2b) which define an end of the material body (3) and spaces (6, 7) which are arranged between adjacent end portions (3a, 3b), which spaces (6, 7) are defined by an inner end surface (la, lb, 2a, 2b) which is located at a distance from de outer end surfaces (la, lb, 2a, 2b), wherein said outer end surfaces (la, lb, 2a, 2b) comprises openings of channels (lc, 2c) which direct a first medium (4) through the material body (3) and that said inner end surfaces (la, lb, 2a, 2b) comprises openings of channels (lc, 2c) which direct a second medium (5) through the material body (3), characterized in that the heat exchanger comprises a clamping device (11, 15) which is adapted to press together the projecting end portions (3a, 3b) until they come contact with each other such that it is provided a tight connection between adjacent end portions (3a, 3b) at at least one end of the material body (3).

2. A heat exchanger according to claim 1 , characterized in the clamping device (11, 15) comprises at least one clamping body (11) which is adapted to press together the projecting end portions (3a, 3b) until they come contact with each other.

3. A heat exchanger according to claim 2, characterized in the clamping body (11) is adapted to be applied in a space (6, 7) between two centrally arranged end portions (3a, 3b).

4. A heat exchanger according to claim 2 or 3, characterized in that the clamping body (11) is shaped such that it presses together the end portions (3a, 3b) in connection with that it is pushed into a space between two adjacent end portions (3a, 3b).

5. A heat exchanger according to claim 2, characterized in that the clamping device comprises two clamping bodies (11) which are adapted to be arranged externally of the outermost located end portions (3 a, 3b).

6. A heat exchanger according to any one of the preceding claims, characterized in that the clamping device comprises a band element (15) which is applied around the end portions (3a, 3b) at an end of the material body (3).

7. A heat exchanger according to any one of the preceding claims, characterized in that said outer end surfaces (la, lb, 2a, 2b) are arranged in a common first plane (Ai, Bi) and that said inner end surfaces (la, lb, 2a, 2b) are arranged in a common second plane (A₂, B₂).

8. A heat exchanger according to any one of the preceding claims, characterized in that the material body (3) is made of first channel elements (1) and second channel elements (2) which are alternately stacked on each other.

9. A heat exchanger according to any one of the preceding claims 1 to 7, characterized in that the material body (3) is manufactured as a coherent unit.

10. A heat exchanger according to any one of the preceding claims, characterized in that the heat exchanger comprises a casing (8) which encloses the material body (3).

11. A heat exchanger according to claim 10, characterized in that the casing (8) comprises at least one inlet (8a, 8b) to direct one of said mediums via a side opening (6a, 7a) to said space (6, 7).

12. A heat exchanger according to claim 10 or 1 1, characterized in that the casing (8) comprises at least one outlet (8c) to receive one of said mediums via a side opening (6a,

7a) from said space (6, 7).

13. A heat exchanger according any one of the claims 10 till 12, characterized in that the casing (8) comprises a wall surface (8d) which is adapted to cover a side opening till (6a, 7a) to at least one of said spaces (6, 7).

14. A method for manufacturing a heat exchanger which comprises a material body (3) comprising a plurality of projecting end portions (3a, 3b) which comprise outer end surfaces (la, lb, 2a, 2b) defining an end of the material body (3) and spaces (6, 7) which are arranged between adjacent end portions (3a, 3b), which spaces (6, 7) are defined by an inner end surface (la, lb, 2a, 2b) which is located at a distance from the end of the material body, wherein said outer end surfaces (la, lb, 2a, 2b) comprise openings of channels (lc, 2c) which direct a first medium (4) through the material body (3) and that said inner end surfaces(la, lb, 2a, 2b) comprise openings of channels (lc, 2c) which direct a second medium (5) through the material body (3), characterized by the step of pressing together the projecting end portions (3a, 3b) until they come in contact with each other such that a tight connection is provided between adjacent end portions (3a, 3b) at one end of the material body (3).

15. A method according to claim 14, characterized by the step of pressing together the projecting end portions (3a, 3b) by means of at least one clamping body (11).