Heat exchanger

A heat exchanger for transferring heat between two fluids with different temperature includes a first heat exchange element having at least one core extending longitudinally through the heat exchange element. The at least one core defines a core cavity that is configured with an inlet port and an outlet port to receive a first fluid flowing therethrough. The heat exchange element includes ribs extending continuously substantially in parallel with the at least one core along the whole length of the core. The ribs extend radially outwardly from the core and are exposed to contact with a second fluid that flows along said ribs. Each rib is divided into at least two radially extending fins at a radial distance from the core. Each fin extends to a proximity of an outer casing surrounding the first heat exchanger element or a proximity of fins of an adjacent heat exchanger element.

FIELD OF THE INVENTION

The present invention relates to a heat exchanger, whereby a first fluid having a first temperature heats up or cools down a second fluid having a second temperature.

TECHNICAL BACKGROUND OF THE INVENTION

In general, heat exchangers are devices that transfer thermal energy between two fluids without direct contact between the two fluids. A primary fluid is typically directed through a fluid core of the heat exchanger while a secondary cooling or heating fluid is brought into external contact with the fluid core. In this manner, thermal energy may be transferred between the primary and secondary fluids through the walls of the fluid core.

The ability of the heat exchanger to transfer thermal energy between the primary and secondary fluids depends on, amongst other things, the surface available for the heat transfer and the thermal properties of the exchanger materials.

A vast number of various types of heat exchangers exist in the field. One of these is disclosed in U.S. 20090084520. This publication shows a heat exchanger comprising a plurality of hexagonal elongate elements, each of the elements having a central channel for a flow of a first fluid. Around the central channel, the elements comprises a metal foam, which can be of an open cell structure or a combination of an open cell structure and a closed cell structure. A second fluid flows through the metal foam.

A major disadvantage of this heat exchanger is that the metal foam provides a very high flow resistance to the flow of the second fluid.

Another known heat exchanger is GB 637235. This publication shows heat exchanger with heat exchanger elements that transfers heat between two fluids. The heat exchanger elements having ribs that extends radially outwardly from the core. Every second fin is divided into two ribs. The heat exchangers are put together so that the fins produce a honeycomb formation where a fluid can flow. The shape of the ribs and fins do not transfer the heat efficiently between the two fluids. The heat exchanger are equal and only shaped to fit a juxtaposed heat exchanger element. The shape is not fitted to the outer casing surrounding the heat exchanger element. There are some empty space between the casing and ribs/fins of the heat exchanger element which results in uneven heating or cooling of the fluid. The honeycomb formation are also less efficient to transfer heat since there are a large space between the fins and ribs.

The publication CN201229141 shows a heat exchanger elements with ribs that divides into two radially extending fins, but the ribs and fins in this publication are not extending continuously in parallel with the core along the whole length of the core, instead they are helically arranged around the core. This will reduce the flow of the fluid through the heat exchanger element and require more energy to transport the fluid through the heat exchanger. The ribs are also arranged with some space between the ribs which also do not increase the efficiency of the heating or cooling.

None of the publications disclose a heat exchanger element where the inlet port and outlet port are arranged at the same end of the core, which provides a better heat transmission between the fluids.

Other known heat exchangers are shown in DE2742877, BE673093, IT7848277, U.S. Pat. Nos. 3,595,310, 2,729,433, US20090107853, EP305702, AU7943132, GB1413913, US20140000845 and WO201091178. However, common to these is that the flow of one of the fluids is restricted by elements of the heat exchanger. These restrictions increase the need of energy (pressure) to ensure a sufficient flow of the fluid.

Heat sinks are used in electronic system to cool for instance central processing units or graphic processors by dissipating heat into the surrounding medium. Heat sinks having fins that extend from its base and increase the area of heat transfer. The base and fins are in direct contact with the heat source for cooling of the electrical unit.

The heat exchanger according to the invention are not equivalent and not suitable for use in heat sinks for cooling central processing unit or similar electrical units. The heat sinks are much smaller to fit in the electronic device than the heat exchanger according to the invention. In the heat exchanger according to the invention, the heat is transferred from a fluid to another fluid to be used as a heating or cooling of a surrounding gas or a liquid.

SUMMARY OF THE INVENTION

Consequently, there is a need to provide a heat exchanger that ensures a high flow with a minimum of energy consumption to provide the flow. It is also a need to provide a heat exchanger where there is a minimum of loss of pressure difference with an increased flow rate.

Another advantage of the heat exchanger according to the invention is that the surface area of the heat-exchanging element is higher, which results in a more efficient heat transfer. The ribs and fins of the heat exchanger element is adapted to fill the entire cross-sectional area of the heat exchanger so that there are no voids between the heat exchanger elements or the casing and the heat exchanger elements. The heat exchanger elements have a compact structure where the heat transferring area is as great as possible. The heat could thereby be transferred evenly from the first fluid to the second fluid throughout the whole heat exchanger.

A pipe with an inclined opening at the free end will provide better heat transfer to the inner surface of the core. The inclined surface results in a cavitation at the pipe outlet which will lead to turbulence in the fluid towards the inner surface of the core. The turbulence will result in better and more efficient heat transfer from the fluid to the core.

The fins and the ribs have substantially the same thickness in along the radial distance from the core. This provides a better and also more even heat transfer from the ribs/fins to the second fluid throughout the whole heat exchanger.

The material of the heat exchanger causes less incrustation. The exchanger elements are also easier to clean because it can be done by a high-pressure washer. A smooth surface of the ribs/fins is also advantageous in that the fluid can flow through the heat exchanger with a minimum of obstacles. The element could also be made by extrusion. This provides easier production of the elements.

The heat exchanger can be construed by one heat exchanger element or several heat exchanger elements assembled together. This makes the heat exchanger flexible in various use.

The heat exchanger could also have ribs arranged on the inner surface of the core, This provides a greater heat transfer surface to/from the fluid in the core to the surface of the core.

The objective of the invention is achieved by a heat exchanger for transferring heat between two fluids with different temperatures. The heat exchanger comprises a first heat exchange element, said first heat exchange element having at least one core extending longitudinally through the heat exchange element, said at least one core defining a core cavity, said cavity being configured with an inlet port and an outlet port to receive a first fluid flowing there through, said heat exchange element having ribs extending continuously substantially in parallel with the at least one core along the whole length of said core, said ribs extending radially outwardly from the core and being exposed to contact with a second fluid, flowing along said ribs.

The heat exchanger is distinctive in that each said rib is divided into at least two radially extending fins, at a radial distance from the core, each said fin extends to a proximity of an outer casing surrounding said first heat exchanger element or a proximity of fins of an additional heat exchanger element, said additional heat exchanger element being arranged adjacent to said first heat exchanger element, said inlet port and said outlet port being coupled to said core at the same end of the core.

Preferable embodiment of the heat exchanger are defined in the dependent claims, to which reference is made.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1illustrates a heat exchanger1. It facilitates transfer of thermal energy between two or more fluids. The fluids may include liquid, gasses or any combination of liquid and gases. For example, the fluids may include air, exhaust, oil, coolant, water or any other fluid known in the art. The heat exchanger may be used to transfer thermal energy in any fluid systems, such as for example, an exhaust and/or air cooling system, a radiator system, an oil cooling system, a condenser system or any other type of fluid system known in the art.

FIG. 2shows a partially exploded, elevated view of the heat exchanger according to one embodiment of the invention. The heat exchanger1comprising a housing3. This housing3is shown cylindrically shaped but it could also have other shapes, like a rectangular shape.

A heat exchanger2according to the embodiment of the invention is arranged within the housing3. At both ends of the housing3, there are arranged lattices4,5to provide protection for the heat exchanger.

FIG. 3discloses the heat exchanger2according to the invention in greater detail. The heating element2comprises a plurality of heat exchange elements10,11. Each heat exchange element10,11has a core defining a core cavity20,21in the centre of each of the heat exchange elements10,11. The core cavity20,21extends in the longitudinal direction of the heating element2with opening in both ends of the core cavity20,21. The ends are further defined as a first end20a,21a(see alsoFIG. 10) of the core and a second end20b,21bof the core cavity20,21. The cores20,21are sealed with a first plug22in the first end20a,21aand a second plug13at a second end of each of the respective cores20,21. The cores20,21are adapted to be filled with heating agent or alternatively a coolant depending on the purpose of the heat exchanger.

FIG. 3further shows a centre heat exchange element10defining the centre of the heat exchanger2and a plurality of external heat exchange element11located adjacent or in proximity of the centre heat exchange element10.

At least one ring15is extending around the heat exchange elements to lock the heat exchange elements10,11together. The ring15is best shown inFIGS. 5-9. In these figures, there are illustrated two rings15extending around the heat exchange elements at each end of the heating element2.

There is also shown a casing16extending around the periphery of the heat exchange elements11.

FIG. 4discloses the heating elements2, viewed from the opposite side thanFIG. 3. There are a plurality of pipes or tubes12a,12b,12carranged between the cores20,21in order to establish a fluid communication between the cores20,21. The pipe or tubes12a,12b,12ccould also be arranged so that the cores are coupled in parallel configuration instead of the serial configuration shown. This will be described later.

An inlet pipe or tube12aforms the link between the supply source (not shown) of the heating fluid and the inlet of the first end21aof the centre core cavity21in the centre heat exchange element10. The free end of the pipe or tube12apreferably has a male sleeve coupling17afor quick and easy connection with the supply source. This connection is preferably drip-free.

The connection could be a quick release coupling both to the supply tube or supply pipe and to the discharge tube or discharge pipe.

There is another pipe or tube12bextending between a first end21aof the centre core cavity21and a first end20aof the external core cavity20. In addition, there are similar pipe or tubes12bextending between two lateral external cores20of the external heat exchange elements11as shown inFIG. 4.

Different configurations for the connection between the heat exchange elements10,11are shown inFIGS. 25-31. It is also possible to make the heat exchanger2in one element with several core cavities20,21. This is described below.

The outlet pipe or tube12cis in one end coupled to the first end20aof an external core cavity20and the other end is adapted to be connected to a device for receiving the fluid flowing through the core cavity and which is to be heated or cooled.

The free ends of the outlet pipe or tubes are adapted to be connected to arrangements for supply of fluid and discharge of fluid from the core. For instance, the free ends of the outlet pipes of tubes12a,12ccould be provided with quick release coupling for connecting with pipes of tubes attached to the supply/discharge arrangement. Other connection arrangement are also possible.

The inlet pipe12acould optionally be arranged in connection with one of the external cores cavities20and the outlet pipe12ccould optionally be arranged in connection with the centre core cavity21. Different arrangements of the Inlet and outlet pipe or tube to any of the external core cavity20or to the centre core cavity21are possible embodiments of the invention. TheFIG. 4shows just one possible arrangement.

Another possible embodiment of the arrangement of the pipes12a,12cis that there are separate inlet pipes or tubes12aand separate outlet pipes or tubes12cto cores20,21and that there is no fluid connection as pipe or tube12bbetween the cores20,21. This is illustrated inFIG. 31.

FIGS. 5, 6 and 7shows the heating element2without the casing16. The position of the rings15extending around the periphery of the external heat exchange elements11are shown in greater detail in this figure.

The heat exchanger are inFIGS. 5 and 6viewed from the second, or front, side, i.e. the opposite side of the heating or cooling fluid inlet and outlet. The core cavities20,21are in this second end sealed with second plugs13and screws14. The second plug13has packer element13a(seeFIG. 12) that provide a sealing closure between the core cavity20,21and the plug13.

InFIG. 7the heating element is viewed from the first end, i.e. the inlet and outlet side of the heating or cooling fluid.

FIG. 8shows an elevated view of the heating element2where the pipes or tubes12a,12b,12care removed.

FIGS. 9 and 10shows the heating element without the pipe or tubes12a,12b,12c. At the first ends of the core cavities20,21there are arranged first plugs22, each with a sealing packer element23(seeFIGS. 10 and 11). The first plug22has similar configuration as the second plug13and is arranged in each of the core cavities20,21at the first end20aand the second end20bto provide a seal tight connection between the core surface20c,21cand the first plug22and the second plug13.

The first plug22comprises two openings or holes22a,22b, hereinafter referred to as an inlet port22aand an outlet port22b. The openings or ports are extending through the first plug22. The ports22a,22bare arranged next to each other. In connection with the respective ports22a,22bthere is arranged an inlet adapter24and an outlet adapter25at the outside of the first plug22. The inlet and outlet adapters24,25connects the respective inlet pipe or tube12a(FIG. 4) and outlet pipe or tube12c(FIG. 4) together with the first plug22and consequently there is a fluid communication established between the pipe or tubes12a,12b,12cand the core cavity20,21through the ports22a,22b.

At the inside of one inlet port22a, at the inside of the first plug22, there is arranged a small pipe26which can be screwed into the inlet port22afor instance in connection to the inlet adaptor24of the first plug22. This pipe26is extending towards the second plug13at the inside of the core cavity20,21in order to provide circulation of the heating fluid in the core cavity20,21. This will be described in further detail below. The first plug22and the components attached to the plug22is shown in greater detail, in elevated view inFIGS. 11 and 12.

A threaded rod27extends through the core cavity20,21and is attached to the first plug22in a first end. A second end is extending through an opening or hole13bin the second plug13(shown inFIG. 12). A nut50and washer51(FIG. 12) is arranged at the second end of the rod27to secure the second plug13to the core cavity20,21via the rod27. The threaded rod27is securing the first plug22and the second plug13(FIG. 6, 12) together at both ends of the core20a,20b,21a,21b. This is shown inFIG. 12.

FIG. 13shows an exploded elevated view of the external heat exchange element11and the centre heat exchange elements10.

The centre heat exchange element10is in this embodiment surrounded by external heat exchange element11in a circle around the periphery of the centre heat exchange element10. The surface of the external heat exchange element11has at the side facing the centre heat exchange element10, a curved shape which is complementary to the shape of the outer surface of the centre heat exchange element10.

Other embodiments of the invention could have other shapes as shown in the accompanying drawings, as seen particularly inFIG. 25-26where there is no centre heat exchange element10. The outer periphery of the external heat exchange element11could also have different shapes depending on the shape of the casing surrounding the external heat exchange element11, such as in particular shown inFIGS. 21-29.

FIG. 14shows a principle drawing of a single external heat exchange element11with a core cavity20extending from a first20aend to a second end20b. The core cavity20is at the ends delimited by the first plug22and the second plug13. The core cavity20,21has a cylindrical shape, but other shapes are also possible, for instance cubical. This applies both for the centre heat exchange element10and the external heat exchange element11.

The external heat exchange element11as well as the centre heat exchange element10comprises a plurality of longitudinal ribs30. Each rib30,31is extending substantially in parallel with the core cavity20,21and radially outwardly from a surface defining the core cavity20,21.

FIGS. 15aand 15bshows different embodiments of the ribs30and fins33,34of the external heat exchange element11.

FIGS. 16-17andFIG. 38-39shows detailed view of different embodiments of the centre heat exchange element10.

The surface defining the core cavity20,21is shown as a core surface20c. The ribs30,31are extending radially outwardly from the core surface20c.

The ribs30are preferably made of metal or with a smooth surface so as to provide low surface friction, enabling the heated or cooled fluid to pass through the heat exchange element with a minimum of resistance from the ribs30.

At a radial distance from the core surface20cthe rib is preferably split into two or more fins33and34to increase the surface area and thus the area that can transfer heat.FIG. 15shows a first fin33and a second fin34that are extending substantially parallel to each other radially outwardly towards an adjacent or heat exchange element10,11or an outer casing11. The shape of the ribs30,31and fins33,34,35,36could be different in different configurations of the heat exchangers2and are also depending on the use of the heat exchanger2,100.

For instance if the viscosity of fluid, flowing through the gaps between the ribs30,31, is high, it is more suitable to have a greater distance between the fins33,34,35,36and/or the ribs30.31than if the viscosity of the fluid is lower.

The ribs30,31and fins33,34,35,36are preferably extending along the whole length of the core surface20c. The radial extent of the ribs30,31and the fins33,34,35,36could also be different in different configurations of the heat exchanger2,100to match with the different configurations of the surrounding elements.

The ribs has preferably a thickness D of 0.5-1.5 mm but other thicknesses are also possible embodiments of the invention.

The fins could have a thickness d of 0.5-1.5 mm but other thicknesses are also possible embodiments of the invention.

The ribs30,31and fins33,34,35,36are in theFIG. 15aequally disposed around the outer surface20cof the core with a minimum space between the ribs30,31and fins33,34,35,36.

The shape of each extending ribs30,31and fins33,34,35,36is arranged so that there is a minimum of gap between each of the heat exchanger elements10,11or between the casing16and the heat exchanger element10,11to provide a uniform transmission of heat between the fluids in the heat exchanger.

The fins33,34,35,36could preferably have the same thickness d in the whole radial distance from the core surface20c. The ribs30,31could similarly have the same thickness in the radial distance from the core surface20c. The ribs30,31and the fins33,34,35,36could have the same thickness or the thickness of the rib could be different from the fins33,34. The two fins33,34,35,36extending from one rib30,31could be arranged parallel in the radial direction from the core cavity as shown in theFIG. 15a. The two fins33,34attached to one rib30having equal distance M in the radial distance from the core surface20c. The fins of one ribe are parallel.

The fins33,34,35,36could also be arranged so that there is equal distance P between two neighboring fins33,34,35,36which means that the two fins33,34,35,36extending from one rib30,31is arranged with an angular distance S which are the same between the fins of one rib. The two neighbouring fins of two different ribs are therefore parallel. This is illustrated inFIG. 15b.

Another possibility is that all the fins are disposed with the same angular distance between each of the fins (not shown)

The angular distance A between two ribs30,31arranged on the surface of the core20ccould also be equal disposed around the whole surface of the core cavity20,21.

There could also be more than two fins (33,34,35,36) extending from each rib (30,31).

The centre heat exchange element10could have similar configuration with ribs31and fins35,36as the external heat exchange element11described above.FIG. 16-17shows one embodiment of the ribs31and fins35,36with similar shape as described inFIG. 15a.

Each of the fins33,34,35,36of the centre or the external heat exchanger element10,11that are facing the casing16are extending to a proximity of the outer casing16. The remaining fins33,34,35,36are extending to a proximity of the fins33,34,35,36of an adjacent or nearby heat exchanger element10,11. Each of the fins has thus a shape so that there is a uniform distribution of fins throughout the whole heat exchanger and that there is no voids between the casing16and the different heat exchanger elements10,11or between the juxtaposed heat exchanger elements10,11. This is illustrated in theFIGS. 2-10andFIG. 21-30.

The inside surface of both the centre heat exchange element10and the external heat exchange element11could also have different embodiments.

InFIG. 16-20there are shown examples with inner ribs37extending radially inwards from the inner core surface20c′ illustrated on a centre heat exchange element10. The external heat exchange element10could as an option have ribs37of different shapes extending radially inwards from the inner core surface20csimilar to the embodiments of the centre heat exchange elements10shown theFIG. 16-18.

In a further embodiment of the invention, each of the inner ribs37could be split into two radially extending fins38,39as shown inFIG. 17.

The inner ribs37could optionally be arranged in a separate inner core element40that may be press fit into the centre heat exchange element10at the inside of the core surface21c. This is shown inFIG. 18. This separate inner core40shown inFIG. 19-20could also be suitable for use in external heat exchange element11.

FIGS. 19 and 20show the inner core element40separated from the centre heat exchange element10with different configurations of the inner ribs37.

The inner core surface21c′ of the centre heat exchange element10could also be smooth as shown in the external heat exchange element11as shown for instance inFIGS. 15aand 15b, this being a possible embodiment of the invention.

The centre and external heat exchange elements10,11and also the inner core element40can be extruded, so that the core surface20c,21cand ribs30,31with fins33,34,35,36are made in one piece and of one material. Suitable material for the heat exchange elements10,11and inner core element40are materials with high thermal conductivity, such as metal, for instance aluminium or copper. Other metals that have good heat conductivity and are suitable for extruding, may also be used.

The heat exchanger could also be extruded in one piece with a plurality of cores to a shape as for instance as shown inFIG. 21 or 22.

The plurality of ribs and fins are then extending between two cores and integrally arranged with the core surface at both ends of the ribs or fins.

The heat exchange elements10,11could also possible be made from 3D printing of the heat exchange elements10,11or core element40. The development of 3D printing is fast and this may prove to be a feasible method in the near future, especially for producing smaller sized heat exchangers2.

FIGS. 21-29show different designs of the heat exchange elements10,11and gives examples of different assembly configurations that are possible for the heat exchanger with several heat exchanger elements.

InFIG. 21the centre heat exchanger element is cylindrical and eight external heat exchange elements11are arranged in on the outside of the centre heat exchange element10forming a cylindrical ring surrounding the centre heat exchange element10. This heating element has nine core cavities20,21adapted for the supply of the heating agent or coolant.

InFIG. 22the centre heat exchange element10has a similar cylindrical shape, but there are only four external heat exchange elements11on the outside of the centre heat exchange element10surrounding the centre heat exchange element10. The heating element2thus having five cores20,21for supply of the heating agent or coolant. The fins extending radially outwardly from the core are also longer than in the embodiment described inFIG. 22. The gap between the ribs30at their outer portions will therefore be larger.

FIG. 23shows yet another embodiment of the invention with different shape of the heat exchanger. This results in a different shape of the external heat exchange elements11. In this embodiment, the heat exchanger has a cubic shape. The outer surfaces of the external heat exchange elements11are straight and perpendicular to each other. The centre heat exchange elements10is cylindrical, resulting in that the surface of the external heat exchange elements11is concave and has a corresponding curved shape as the outer surface of the centre heat exchange element10.

FIG. 24shows yet another possible embodiment of the invention, where a plurality of the heat exchange elements shown inFIG. 24are assembled to form a heat exchanger with a plurality of centre heat exchange elements10and a plurality of external heat exchange elements11.

FIGS. 25-26show another embodiment of the invention where the heat exchanger is composed of four external heat exchanger elements11. In this embodiment, there is no centre heat exchange element10.

FIG. 27shows the same embodiment of the invention as shown inFIG. 21with tubes or pipes12barranged between the cores

InFIGS. 28 and 29there is an additional layer of external exchange elements111arranged in a circle around the initial layer of external exchange elements11.

The number of external heat exchange elements11is not limited to the embodiments of the drawings. Other numbers of external heat exchange elements11,111suitable for the invention is also possible.

Each of the heat exchange element10,11,111forming the heat exchanger in theFIG. 21-29could be assembled by separate heat exchanger elements that are adjoining each other in a preferred shape so that the heat exchanger elements creates a heat exchanger where the ribs and fins are extending in the whole cross sectional area of the heat exchanger and that there is no voids.

It is also possible within the invention to make a heat exchanger element10with a plurality of cores20,21integrated in one heat exchange element, like for instance a shape similar to the shape inFIG. 21.

FIGS. 26-30also show a possible fluid communication between the different heat exchange elements10,11. There is shown a transfer of fluid from the core cavity20,21of one heat exchange element10,11to the core cavity20,21of the adjacent heat exchange element20,21. The fluid is transferred through pipes or tubes12band openings24as shown inFIGS. 4 and 9-10.

The fluid could be supplied to the centre heat exchanger10and thereafter through all of the external heat exchangers11,111before the fluid is discharged from the heat exchanger2. The fluid could optionally be supplied to one of the external heat exchange element11,111and thereafter through all of the external exchanger element11,111before it is discharged from the centre heat exchange element10or from one of the other external exchange element if there are no centre exchange element10as inFIG. 26.

FIG. 31shows another configuration of the supply of fluid to and the return of fluid from the heat exchanger2. In this Figure, there is no pipes or tubes12b, i.e. no fluid connection, between the cores cavities20,21of the heat exchange elements10,11. The heat exchange elements10,11have each a supply of fluid from a separate supply tube or pipe12aand a separate outlet pipe or tube12cfor the return of fluid from the core cavity20,21. The supply pipes12aand the outlet pipes12care coupled to a common delivery and return pipe through a respective manifold. Consequently, the fluid systems are arranged in parallel.

Another arrangement of the supply and distribution of the fluid between the cores20,21could be that the inlet and outlet ports24,25are arranged at opposite ends. This means that the supply tube or pipe12a, outlet tube or pipe12cand the pipes or tubes12bbetween the heat exchange elements are arranged at both ends of the heat exchanger elements10,11.

FIGS. 32-34show yet another embodiment of the invention. In this embodiment, the structure of the heat exchanger100is similar to the centre heat exchange element10as described in previous drawings. The core cavity21has plugs13,22arranged at both ends, the first plug22has openings with an inlet port24and an outlet adapted25, to let the heating medium or coolant flow into and out of the core cavity21. A threaded rod27is attached at both ends to the first plug22and second plug13to secure the plugs13,24at the core ends21a,21b, preferably along a centre axis of the core cavity20,21. The figures also show the pipe26extending from the inlet port22atowards the second plug13to provide circulation of fluid along the full length of the core cavity21. The pipe26has a free end arranged at the proximity or a suitable distance from the second plug13. This second end26ahas an inclined opening as shown in theFIG. 34. The inclined opening is preferably oriented towards the inner core surface20c, but could as an option have other orientations.

The pipe26is arranged offset of the centre axis of the core cavity20. This arrangement of the pipe26gives a better heat transfer through the core cavity21because the pipe outlet shape creates cavitation at the end which results in a turbulence in the fluid towards the inner surface of the inner core surface21c.

This will result in a better heat transfer.

The principle is shown in relation to the centre heat exchange element, but the arrangement with an inclined end pipe26ais also possible in the external heat exchanger11(not shown).

The heat exchange element100has also ribs31and fins35,36extending radially outwardly from the core cavity21.

InFIG. 33there is also shown an embodiment with the inner ribs37as described inFIG. 16-18but the heat exchanger element100could also function without the inner ribs37.

FIGS. 33 and 34show both ribs37that are attached to the inner core surface20cand separate inner core element40that is arranged at the inside of the core.

FIGS. 35-51show different use of heat exchange according to the invention.

FIGS. 35-37shows an embodiment of the heat exchanger where the heat exchanger100, as described inFIG. 33-34, is arranged within a duct41. The heating medium or coolant is supplied and discharged via pipelines12a,12cconnected to couplings that extends through openings in the walls of the duct41. This arrangement is particularly suitable for heat exchanging liquid, such as cooling of oil. The duct41is liquid tight and the liquid to be heated or cooled down flows through the duct41in the longitudinal direction thereof.

FIG. 38-39shows another embodiment of a centre heat exchange element10′. In this embodiment there is a cylinder50attached on the outside of the centre heat exchange element10′. The ribs31with fins35,36are extending from the inner core to the outer cylinder50. This is different from the embodiment of the heat exchange element10fromFIG. 16-18where the centre heat exchange element10do not have this outer cylinder50.

The centre heat exchange element10′ could have inner ribs37extending radially inwards from the core surface21cas shown inFIG. 39or a smooth inner surface as shown inFIG. 38. The inner ribs37will increase the inner surface area of the core21cand hence increase the heat transfer. This embodiment is particularly suitable for use as a terrestrial heat exchanger.

FIGS. 40-46shows a heat exchanger using the centre heat exchange elements10′ fromFIG. 38-39. The centre heat exchange element10′ with the outer cylindrical plate50cylindrical part forms a cylindrical part that could in both ends be connected to pipelines102by for instance a pipe fitting101. This differs from the embodiment ofFIG. 36-38where the centre heat exchange element10is arranged within the duct41and not forming part of the outer surface of the pipeline. The centre heat exchange element10′ do not have an additional outer cylinder fixedly attached to the fins35,36, the outer cylinder forms part of the heat exchanger10′.

FIGS. 42-43show the second plug13and a cap14in greater detail. The second plug13has arrangement for bleeding or aeration of the core cavity20,21. The core cavity20,21is normally filled with a heating agent or coolant but there could also be air bubbles together with the coolant or heating agent in the core cavity20,21.

These bubbles could be removed from the core cavity20,21through a clearance between an opening13bin the second plug13and the threaded rod27that extends through the opening in the second plug as shown inFIG. 42-43. To release the air it is possible to loosen the cap14that is screwed onto the threaded rod27. This is shown in detail inFIG. 12.

The heat exchanger100could be secured to the pipe fittings101in different ways as shown inFIGS. 45-46. InFIG. 46the first plug22and second plug13are arranged in mountings42that are fixed to the inner walls of the fittings101.

FIGS. 47-51show another embodiment of the heat exchanger according to the invention, which is arranged within a duct43. In this embodiment, the heat exchanger2comprises a centre heat exchange element10and a plurality of external heat exchange element11as described inFIG. 3-10. This arrangement is also suitable for heat exchanging liquids but could also heat of cool air.

In yet another embodiment of the heat exchanger according to the invention, there is arranged an electrical heating coil within the core of the heat exchange element10,11to heat the fluid in the core20,21instead of supplying warm fluid externally through pipes or tubes12a,12b,12cas shown in the previous drawings. This is particularly useful in smaller scale as a heating element or where there is not possible to heat the fluid by an external heating source. This could be applied in system for heating gases or system for heating liquid as described in the embodiments above.

FIG. 51shows another example of use of the heat exchanger. The heat exchanger is in this embodiment arranged in connection with a fan or other type of blower30for blowing air through the heat exchanger, and hence blowing heated air into e.g. a building. This illustrates just an example of the use. There are other possibilities of use, being embodiments of the invention

Based on the accompanying drawing and the description of the different parts, a functional explanation of the invention is described hereinafter.

A heating agent or coolant is supplied to the core20,21from the supply source to the core20,21. The heating agent or coolant is supplied via the inlet pipe or tube12a, through the inlet opening22aof the first plug22and through the pipe26so that the heating agent or coolant is led to the opposite end of the core20,21, i.e. towards the second plug13(as shown in different figures for instanceFIG. 42) The heating agent or coolant that enters the core20,21will push the heating agent or the coolant already present in the core20,21towards the outlet opening22band it will flow out of the core20,21towards another core20,21or through the outlet pipe of tube12c.

Optionally the heating agent of coolant could be warmed or cooled by a heating coil or cooling arrangement arranged within the core20,21.

The heating agent or coolant could be either a gas or a liquid. The inside of the core20,21preferably have smooth walls to reduce friction.

In an optional embodiment inner ribs37are formed on the inside of the core surface20cor a removable inner core element40. This can be done for instance by milling. The ribs37increase the surface area and thereby transmission of heat from the heating fluid.

A fluid to be heated or cooled is conducted lengthwise of the ribs30through the heat exchange elements10,11from a first or second end of the heating element towards the opposite end of the heating element2,100.

The fluid is heated or cooled by the transmission of energy through the surface of the core20c, the ribs and the fins.

There is described both a transmission of heat from a heating fluid in the core to a heated fluid throughout the description as well as a cooling process where a coolant is supplied to the core and a fluid to be heated is conducted along the ribs.

The present invention has been described with reference to preferred embodiments and aspects thereof and related to the accompanying drawings for the sake of understanding only and it should be obvious to persons skilled in the art that the present invention includes all legitimate modifications within the ambit of what has been described hereinbefore and claimed in the attached claims.