Counter flow heat exchanger

Abstract

A counter flow heat exchanger: has an inner container with radially outwardly projecting helical webs, a cylindrical housing, wherein an inner circumferential surface of the housing and the radially outer edges of the helical webs of the inner container are in contact such that a flow path is developed in which a first heat transfer fluid can flow between the helical webs of the inner container and the inner circumferential surface of the housing; a helical heat exchanger tube extending between the helical webs of the inner container such that a second heat transfer fluid can flow within this heat exchanger tube counter to the direction of flow of the first heat transfer fluid. A method for the production of a counter flow heat exchanger is also provided.

Claims

1. A counterflow heat exchanger comprising: an inner container with radially outwardly projecting helical webs; a cylindrical housing, wherein an inner circumferential surface of the housing and the radially outer edges of the helical webs of the inner container are in contact such that a flow path is developed in which a first heat transfer fluid can flow between the helical webs of the inner container and the inner circumferential surface of the housing; a helical heat exchanger tube extending between the helical webs of the inner container such that a second heat transfer fluid can flow within this heat exchanger tube counter to the direction of flow of the first heat transfer fluid; wherein the radially outwardly projecting helical webs of the inner container are comprised of two-component synthetic material, wherein a radially outer section of the helical webs is comprised of a softer synthetic material than a radially inner section of the helical webs and the radially outer section of the helical webs is deformed by the inner circumferential surface of the housing.

2. A counterflow heat exchanger according to claim 1, wherein the helical heat exchanger tube has a smooth outer peripheral surface and does not comprise ribs.

3. A counterflow heat exchanger according to claim 1, wherein the helical heat exchanger tube comprises longitudinal ribs extending in the elongated state in the axial direction on the outer surface of the heat exchanger tube.

4. A counterflow heat exchanger according to claim 1, wherein the helical heat exchanger tube and the radially outwardly projecting helical webs have the same pitch in the axial direction.

5. A counterflow heat exchanger according to claim 4, wherein the housing comprises the plastically deformable material 15.

6. A counterflow heat exchanger according to claim 1, wherein the housing is comprised of ductile or plastically deformable material.

7. A counterflow heat exchanger according to claim 1, wherein the radially outwardly projecting helical webs of the inner container comprise at least one discontinuity.

8. A counterflow heat exchanger according to claim 1, wherein the helical heat exchanger tube is not in contact with the housing and/or the inner container.

9. A method for the production of a counter flow heat exchanger comprising the following steps: providing an inner container with radially outwardly projecting helical webs and a helical heat exchanger tube, wherein the pitch of the helical heat exchanger tube corresponds to the pitch of the helical webs of the inner container; threading the helical heat exchanger tube between the turns of the helical webs of the inner container; providing a cylindrical housing of the counter flow heat exchanger, wherein the diameter of the inner circumferential surface of the cylindrical housing is laid out such that it at least corresponds to the diameter of the radially outer edges of the helical webs of the inner container or that the diameter of the helical webs of the inner container is greater than the inner circumferential surface of the cylindrical housing; generating a sealed-off flow path between the helical webs of the inner container and the housing through the contact between the radially outer edges of the helical webs of the inner container and the inner circumferential surface of the cylindrical housing; wherein the housing is comprised of a ductile or plastically deformable material such that the generation of the sealed flow channel is completed by means of applying, in particular impressing, external mechanical forces on the housing at the radially outwardly projecting helical webs of the inner container.

10. A method according to claim 9, wherein the radially outwardly projecting helical webs have a greater diameter than the inner circumferential surface of the housing, wherein the radially outer edges of the helical webs of the inner container during the generation of the sealed flow channel contacts with the inner circumferential surface of the housing and are deformed.

11. A method for the production of a counter flow heat exchanger comprising the following steps: providing an inner container with radially outwardly projecting helical webs and a helical heat exchanger tube, wherein the pitch of the helical heat exchanger tube corresponds to the pitch of the helical webs of the inner container; threading the helical heat exchanger tube between the turns of the helical webs of the inner container; providing a cylindrical housing of the counter flow heat exchanger, wherein the diameter of the inner circumferential surface of the cylindrical housing is laid out such that it at least corresponds to the diameter of the radially outer edges of the helical webs of the inner container or that the diameter of the helical webs of the inner container is greater than the inner circumferential surface of the cylindrical housing; generating a sealed-off flow path between the helical webs of the inner container and the housing through the contact between the radially outer edges of the helical webs of the inner container and the inner circumferential surface of the cylindrical housing; wherein the radially outwardly projecting helical webs of the inner container are comprised of two-component synthetic material, wherein a radially outer section of the helical webs is comprised of a softer synthetic material than a radially inner section of the helical webs and in generating the sealed flow channel the radially outer section of the helical webs is deformed by the inner circumferential surface of the housing.

12. A method according to claim 11, wherein the radially outwardly projecting helical webs have a greater diameter than the inner circumferential surface of the housing, wherein the radially outer edges of the helical webs of the inner container during the generation of the sealed flow channel contacts with the inner circumferential surface of the housing and are deformed.

Description

BRIEF DESCRIPTION OF THE DRAWING

(1) With reference to schematic drawings a counter flow heat exchanger according to an exemplary embodiment will be described in the following. General examples of such devices are utilized for example in motor vehicles to carry out the air conditioning of a passenger compartment. Additional modifications of certain individual characteristics described in this connection can each be individually combined with one another in order to show new embodiments. In the drawing depict:

(2) FIG. 1: a schematic representation of an inner container with radially outwardly projecting helical webs;

(3) FIG. 2: a schematic representation of a helical heat exchanger tube;

(4) FIG. 3: a schematic representation of threading the helical heat exchanger tube in the axial direction between the radially outwardly projecting webs of the inner container;

(5) FIG. 4: a cross sectional representation along the axial direction of the heat exchanger of a counter flow heat exchanger according to an exemplary embodiment of the present invention;

(6) FIG. 5: an enlarged partial cross sectional representation of the flow path between the radially outwardly projecting helical webs of the inner container and the housing with a heat exchanger tube extending helically thereinbetween.

DESCRIPTION OF THE PREFERRED EMBODIMENT

(7) FIG. 1 shows a schematic representation of an inner container 10 with radially outwardly projecting helical webs 12. These radially outwardly projecting helical webs 12 extend from the shell surface 11 that corresponds to the outer peripheral surface of the cylindrical inner container 10. The webs 12 exhibit herein a constant spacing between the particular turns of the webs 12. Stated differently, they have a constant pitch along the axial direction of the inner container 10. The representation shows, moreover, that the helical webs 12 have a constant outer, peripheral diameter.

(8) In the embodiment example depicted in FIG. 1 of the present invention the webs 12, radially outwardly projecting from the shell surface 11 of the cylindrical inner container 10, are implemented integrally with the shell surface 11 of the inner container 10. This means that the inner container 10 without any further machining can preferably be produced as a single part with the radially outwardly projecting helical webs 12, for example using an injection molding process. Consequently, constant wall thicknesses at simultaneously cost-effective fabrication of the inner container 10 with radially outwardly projecting helical webs 12 can be realized integrally.

(9) In a further embodiment, not shown, it is feasible for the radially outwardly projecting helical webs 12 of the inner container 10 to be deformable and/or be implemented of a two-component synthetic material.

(10) In the exemplary embodiment of the present invention on the upper side and underside, thus at the axial ends of the inner container 10, closure elements 13 are provided. The closure elements 13 generate the necessary upwardly and downwardly axial delimitation of the inner container 10 in which excess coolant fluid from an air-conditioning system can be collected.

(11) Furthermore, to enable in precise and simple manner a connection of the inner container 10 to the further coolant circulation, FIG. 1 shows the coolant inlet pipe 14 provided for this purpose at the upper axial end of the inner container 10, such that in the assembled state of the counter flow heat exchanger excess coolant can be received within the inner container 10 through the coolant inlet pipe 14.

(12) FIG. 1 additionally shows a cylindrical base element 15 for the axial staying of the inner container 10 within the counter flow heat exchanger. This base element 15 is disposed on the axial underside of the inner container 10 and the outer diameter of the base element 15 conforms with that of the shell surface 11 of the inner container 10. The lower closure element 13, further, can be disposed within the base element 15 and the height of the base element 15 is herein at least as great as the height of the closure element 13 of the inner container 10.

(13) In the embodiment depicted in FIG. 1 of the inner container 10 all parts, in particular the shell surface 11 with the integrally implemented radially outwardly projecting helical webs 12, the upper and lower closure elements 13, the coolant inlet pipe 14 and the base elements 15 can be comprised of synthetic material and implemented by means of injection molding. However, other materials and fabrication methods are also feasible without deviating from the scope of the invention. Through this implementation the machining-free and cost-effective fabrication of the inner container 10 implemented thusly can be realized. It should be ensured that the temperature resistance and the material properties of the inner container 10 and the additional elements are selected such that they withstand the temperatures and pressures occurring during the heat exchange without impairment of the materials.

(14) FIG. 2 is a schematic representation of a helical smooth heat exchanger tube.

(15) In the exemplary embodiment depicted in FIG. 2 the helical heat exchanger tube 21 is provided on the upper and lower end in the axial direction with connection elements 22 to enable therewith the connection to the further coolant circulation of an air-conditioning system. In addition, the connection elements 22 permit the positioning and securing of the helical heat exchanger tube 21 between the helical webs 12 of the inner container 10.

(16) These connection elements 22 can be fixed in place by simply being pressed or clamped onto the heat exchanger tube 21. Other embodiments, however, are also conceivable as long as a sealing that withstands the occurring pressures and temperatures can be generated between the two elements. Furthermore, the integral implementation of the two elements, thus of the connection elements 22 and of the heat exchanger tube 21, is feasible in a further embodiment.

(17) The heat exchanger tube 21 has a helical structure that extends in the same direction as the radially outwardly projecting helical webs 12 of the inner container 10. Furthermore, the radius of the helical windings of the heat exchanger tube 21 is selected such that it is greater than the radius of the shell surface 11 of the inner container 10.

(18) FIG. 3 shows furthermore that the webs 12 and the heat exchanger tube 21 in the exemplary embodiment have the same pitch and the radial spacing between the individual turns of webs 12 is large enough so that the heat exchanger tube 21 can wind between the individual turns of webs 12 free of contact. This exemplary implementation makes it possible, on the one hand, for the heat exchanger tube 21, as shown in FIG. 3, to be simply and quickly threaded in, while, on the other hand, damage to the sensitive parts can be avoided. Further, thereby the entire surface of the heat exchanger tube 21 can be utilized for the heat transfer. This permits the most efficient heat transfer possible in the finished counter flow heat exchanger.

(19) FIG. 4 shows in this regard a cross sectional view along the center axis of the inner container 10 which simultaneously is also the center axis of the helical heat exchanger tube 21 and of the cylindrical housing 30.

(20) After the threading, as shown in FIG. 3, of the heat exchanger tube 21 between the webs 12 of the inner container 10 has been completed, by emplacing the cylindrical housing 30 the flow path between the radially outwardly projecting helical webs 11 and the housing 30 is implemented. The radially inner circumference of housing 30 is implemented such that it comes into contact with the radially outer edges of the helical webs 12 and, by means of form closure, an adequate connection is generated such that a sealing is formed and the flow path can be developed. This flow path conducts a first heat transfer fluid and enables in this way the heat transfer between the inner container and the second heat transfer fluid conducted in the heat exchanger tube 21. Particular is herein that the first heat transfer fluid flows counter to the direction of the second heat transfer fluid such that as efficient a heat transfer as possible can be realized in a compact implementation.

(21) The cylindrical housing 30 forms the radially outer peripheral surface of the counter flow heat exchanger. For the closure of the counter flow heat exchanger in the axial direction a lower closure element 31 is developed on the underside. In this lower closure element 31 the inner container 10 can be positioned by means of base element 15 that supports the inner container 10 in the axial direction and fixed in place in the recess 33 provided for this purpose. The diameter of the cylindrical recess 33 on the upper side of the lower closure element 31 herein corresponds to the diameter of the cylindrical base element 15.

(22) On the axially upper side of the counter flow heat exchanger shown in FIG. 4, additionally, an upper closure element 32 is developed. The upper closure element 32 comprises herein a first opening 34 for the excess coolant of the air-conditioning system, which simultaneously is the first heat transfer fluid flowing through the flow path. The first heat transfer fluid can accordingly be introduced into the inner container 10 into the inner container 10 through the first opening 34 by means of the coolant inlet pipe 14. Herein, in addition, through the connection of the first opening of the upper closure element 32 with the coolant inlet pipe 14 of the inner container 10, together with the connection of the base element 15 and the recess 33 at the lower closure element 15, the position of the inner container 10 is secured in the counter flow heat exchanger.

(23) The upper closure element 32 comprises further a second opening 35 through which the second heat transfer fluid can be transferred by means of the connection element 22 to the heat exchanger tube. Consequently, the second heat transfer fluid flows in the heat exchanger tube counter to the direction of the first heat transfer fluid in the inner container 10 and in the flow path between the shell surface 11 of the inner container 10, the inner circumferential surface of housing 30, and the radially outwardly projecting helical webs 12.

(24) Positioning the heat exchanger tube 21 in place is further secured through the fixing projections 23 of the connection element 22. The fixing projections 23 are integrally developed projections that are received in the upper closure element 32.

(25) As shown in FIG. 4 the lower and upper closure element 31 and 32 delimit the axial end of the counter flow heat exchanger. In the exemplary embodiment the sealing at the axial ends is accomplished by means of form closure. This is realizable, for example, by means of pressing the closure elements onto the cylindrical housing 30. In a further embodiment it is feasible for this to be carried out by material closure such as by means of welding, soldering or adhesion. Other fabrications processes, however, are also feasible without deviating from the scope of the invention.

(26) Generally, the radially outwardly projecting webs 12, as well as the shell surface 11 and the inner circumferential surface of the cylindrical housing 30 consequently delimit the flow path along which the first heat transfer fluid flows helically and in which the heat exchanger tube 21 is developed.

(27) The more precise flowing characteristics of the first and the second heat transfer fluid in the flow path and in the heat exchanger tube is explained in the enlarged representation of the heat transfer region shown in FIG. 5.

(28) As shown in FIG. 5, the heat transfer takes place between the above described flow path and the outer peripheral surface of the heat exchanger tube 21. Since in the heat exchanger tube 21 a fluid with very high density, liquid density, flows as the second heat transfer fluid, the inner cross sectional area of the heat exchanger tube 21 can be smaller than the cross sectional area of the flow path. In the flow path itself the first heat transfer fluid flows counter to the direction of the second heat transfer fluid in the heat exchanger tube 21, Consequently, due to the oppositely flowing heat transfer fluids, the desired heat transfer takes place efficiently in counter flow.

(29) In other, not depicted, embodiments, it is further conceivable for the heat exchanger tube 21 to comprise ribs in the axial direction of the inner container in order to increase the heat transfer efficiency further.

(30) According to the above device and the above method it is feasible to produce cost-effectively and quickly an efficient counter flow heat exchanger from a small number of parts.

LIST OF REFERENCE NUMBERS

(31) 10 Inner container

(32) 11 Shell surface

(33) 12 Webs

(34) 13 Closure element of the inner container 10

(35) 14 Coolant inlet pipe

(36) 15 Base element

(37) 21 Heat exchanger tube

(38) 22 Connection element

(39) 23 Fixing projections

(40) 30 Housing

(41) 31 Lower closure element of the counter flow heat exchanger//housing

(42) 32 Upper closure element of the counter flow heat exchanger//housing

(43) 33 Recess

(44) 34 First opening

(45) 35 Second opening