EP1819979A1

EP1819979A1 - Cooling device

Info

Publication number: EP1819979A1
Application number: EP05802569A
Authority: EP
Inventors: Björn GUDMUNDSSON
Original assignee: Gudmundsson, Björn
Current assignee: GTHERM AB
Priority date: 2004-11-12
Filing date: 2005-11-11
Publication date: 2007-08-22
Also published as: SE527867C2; SE0402768L; US20080251238A1; WO2006052205A1; SE0402768D0; CN101072977A

Abstract

A cooling device comprising a rotating part (1) provided with an internal space (3) intended for the transport of cooling liquid and provided with external fins (4) intended for the transport of gas along at least a section of the rotating part. The rotating part is symmetrical in rotation and revolves around an axis of rotation (2) . The rotating part comprises a cooling liquid pump section (5) , a fan section (6) , and between these an intermediate section (7) arranged around the axis of rotation, where the fan section has a basic shape of a radially extended plate (15) , wherein the flow of cooling liquid enters at the pump section from an object to be cooled, proceeds through the intermediate section and turns back in the vicinity of the periphery (17) of the fan section, in order to once again pass the intermediate section and then be pumped back to the object by means of the pump section.

Description

COOLING DEVICE

The present invention relates to a cooling device comprising a rotating part provided with an internal space intended for liquid transport of cooling liquid, and provided with external fins intended for air transport along at least a section of the rotating part. For example, the cooling device is intended for vehicle engines, such as combustion engines or electric engines, or other objects in need of heat exchange .between a liquid and a gas, such as air. One example of such objects is heat pumps. As readily understood by the skilled person, it is not necessarily a matter of cooling, but any kind of heat exchanging may be relevant.

State of the art

Conventional systems for cooling, e.g., vehicle engines of today are based on liquid cooled engine blocks and a radiator. The system also includes a liquid pump and a radiator fan. The conventional systems are associated with obvious drawbacks by being comprised of several different, typically expensive, components requiring hose couplings between them, and by requiring that a vacuum is applied in the system in order to avoid air bubbles in the system. Furthermore, the system takes up a great deal of space.

Summary of the invention

It is an object of the present invention to avoid the drawbacks mentioned above. This can be solved by means of a cooling device according to claim 1. Brief description of the drawings

The present invention will now be described by means of exemplary embodiments of the invention and with reference to the attached drawings, in which:

Fig 1 illustrates an embodiment of the present invention, Fig 2a illustrates a first embodiment of the location of the external fins on the plate (only a few fins are shown) ,

Fig 2b illustrates a partial side view of the first embodiment, Fig 3a illustrates a second embodiment of the location of the external fins on the plate, (only a few fins are shown) ,

Fig 3b illustrates a cross section A-A of the second embodiment, Fig 4a illustrates a third embodiment of the location of the external fins on the plate (only a few fins are shown) ,

Fig 4b illustrates a partial side view of the third embodiment, Fig 5a illustrates a fourth embodiment of the location of the external fins on the plate (only a few fins are shown) ,

Fig 5b illustrates a cross section A-A of the fourth embodiment, Fig 6a illustrates a fifth embodiment of the location of the external fins on the plate (only a few fins are shown) ,

Fig 6b illustrates a cross section A-A of the fifth embodiment, Fig 7a illustrates a second embodiment of the present invention having an air pervious material (only a few fins are shown) ,

Fig 7b illustrates a cross section A-A of the second embodiment, and

Fig 8 illustrates a side view of a third embodiment of the present invention having a corrugated plate.

Detailed description of preferred embodiments In fig 1, an embodiment of a cooling device according to the present invention is shown. The cooling device comprises a rotating part 1 being symmetrical in rotation that can be revolved around an axis of rotation 2 by means of driving, e.g., the object or the engine to be cooled or an electrical engine. The rotating part 1 has an internal space 3 intended for liquid transport of cooling liquid through the rotating part, in order to achieve the actual heat exchange between warm cooling liquid coming from the engine to be cooled which is conducted through the internal space 3 of the rotating part 1, whereby the heat is absorbed and discharged to the surrounding air, such that chilled cooling liquid can flow back into the engine in order to cool it once again.

The rotating part 1 is further provided with external fins

4 in order to increase the transport of air along at least a section of the rotating part 1, and the fins 4 may also form an enlarged heat exchanging surface towards surrounding gas/air.

The rotating part 1 comprises three main sections, namely a cooling liquid pump section 5, a fan section 6 and an intermediate section 7 connecting the two former sections

5 and 6, the three sections being arranged around the axis of rotation 2. The cooling liquid pump section 5 is provided with an impeller 8 pumping the cooling liquid back again into the engine or object when cooling is needed or initially via the rotating part 1 if desired, before the cooling liquid returns to the engine or object.

Preferably, a fixed housing 9 is provided around the rotating pump section 5, its impeller 8 and the rotating part 1 being journalled in the fixed housing 9 by means of one or more bearings 10, such as ball bearings, and provided with sealings 11 against the cooling liquid. An outlet 12 from the housing 9' directs the cooling liquid back to the engine or object to be cooled.

The intermediate section 7 is provided with at least two internal channels, optionally arranged concentrically along the axis of rotation 2, an inlet channel 13 for incoming cooling liquid to be cooled inside the rotating part 1, and an outlet channel 14 for ^'the cooling liquid to be pumped back to the engine via the pump section 5. The intermediate section 7 may be extremely short and is regarded as merely an inlet or outlet, respectively, from the fan section 6.

The fan section 6 has the basic form of a radially extending plate 15, in its centre on a first side 18 of the plate 15 being interconnected with the intermediate section 7. The interconnection is made such that the inlet channel 13 and the outlet channel 14 are interconnected with at least one cooling liquid channel 16 inside the plate 15 which at least conducts the cooling liquid from the inlet channel 13 in the vicinity of the centre of the plate 15 out to its periphery 17. At least one cooling liquid channel 21 conducts the cooling liquid back towards the centre to the outlet channel 14 in the intermediate section 7.

The cooling liquid channels 16 and 21 may be a rotary symmetrical cavity, but may also be, e.g., subdivided peripherally or as radial channels. It is not required that the cooling liquid channels 16 and 21 have the same form. A partition wall 22 separates the channels 16 and 21, and the channels 16 and 21 are interconnected by means of a section having at least one channel 23 in the axial direction at the periphery 17.

The plate 15 is provided with external fins 4 on a second side 19 opposite the first side 18, and/or on the first side 18, and/or along its periphery 17. The external fins 4 are arranged to provide a fan action at the fan section 6 such that more air or gas comes into contact with the fan section 6, wherein a greater level of heat exchange is obtained. As mentioned above, the fins 4 may also be utilized to form an enlarged heat exchanging surface.

The fins 4 may be arranged radially and axially, see fig 2a+b, or slanting down radially over the plate 15 at an angle to the axis 2 as seen in the rotary direction, in order to force down the air being at a higher level over the plate surface 15 towards the surface, see fig 3a+b. The contrary is also possible, i.e. when the fins 4 are inclined in the opposite direction as seen in the rotary direction, such that the air is exhausted away from the plate surface 15 and is replaced by new air, which may be favourable also for the heat exchange action.

Preferably, regardless of the angle to the axis 2, the fins 4 are also curved radially, like fans are formed conventionally, in order to increase its fan action, see fig 4a+b and 5a+b. Another exemplary design of the external fins 4 is when being broken up with alternating inclinations to the axis 2 radially, see fig βa+b. Also in this embodiment, it is possible to design the fins curved radially (not shown) .

In order to enable the passage of air adjacent to the plate 15 at its outermost periphery 17, a slit may be provided between the plate 15 and the fin 4 at the radially outer section of the fin 4.

According to a second embodiment of the fan section 6, see fig 7, a number of blocks arranged in rotational symmetry (not shown) , or a circular section 20 of an air pervious material having favourable heat exchanging properties, such as a sintered material of copper, aluminium or Carbon Graphite Foam or a conductive plastic material, are arranged radially inside regular fan fins 4, which fan fins 4 can be displaced radially outwards. The cooling liquid channel (s) 16 and/or 21 in the plate 15 may then be branched, e.g. by means of pipes 24, such that at least a certain partial flow of the cooling liquid flow runs through these blocks or circular section 20. Cooling liquid channels in the form of pipes may in that case be "incorporated" in the air pervious material by means of, e.g., forming by casting, laser working or drilling. Inserting cooling liquid channels in the air pervious material through the blocks or circular section 20 can also be effected by forming cavities in the material, without the use of pipes.

The radially inner section of the blocks or circular section 20 or internal surface facing the centre, may preferably be formed with a certain axial inclination, e.g. by being shaped conically or with a certain angle of repose, thereby allowing larger objects such as leaves, in the case they tend to settle upon the blocks or circular section 20, to pass by. This implies that the shape of the interior surface is given such an inclination along the radius relative to the axis of rotation, that the frictional forces or other forces acting to maintain these larger objects on the radial interior surfaces of the blocks, become smaller than the ejecting centrifugal forces acting at occurring rotation speeds.

According to a third embodiment, the plate 15 has a corrugated shape in order to increase the area of contact and/or thermal transmission towards the air, see fig 8. As mentioned above, different types of fins can be arranged on the corrugated plate 15.

According to an embodiment not shown, the orifice size of the air channel inlet is formed such that particles of dirt, mud and dust are not inclined to get caught and be accumulated in the inlet. Preferably, the size of the orifice is a few millimetres or greater. The inlet is preferably formed with angles of repose such that the centrifugal force exceeds the frictional force at occurring rotation speeds, thereby preventing the accumulation of particles of dirt, mud and dust.

It is known per se that rotating plates containing liquid to be heat exchanged towards air can be provided with pipes protruding from the plate in order to increase the surface of heat transmission. It is also known from GB 1 435 435 that such pipes protruding from the plate may be provided with annular sheets mounted on the pipes protruding from the plate or rotating body, such that a laminated bundle is obtained around the pipes. This is to accomplish a surface enlargement from the pipes towards the surrounding air flow. However, a drawback with such a design is that the pipes, which may be considered to extend in the liquid flow direction out from the plate, are re-directed at the outermost position of the plate where they extend roughly parallel to the plate, and are thereafter given an inward extension towards the plate again. At the area of re-direction, fin members are lacking, or the fin members becomes considerably sparser as a result from being positioned perpendicular to the pipe extension due to manufacturing aspects. Of course, it is possible to attach fin members along the pipe extension in this area, but the geometrical heat exchange surface of the fin is reduced for each pipe length. Furthermore, this requires a very complicated fabrication process, and is therefore not used. On the other hand, if fin members positioned perpendicularly around the pipe are desired in this area, these members require inward space towards the plate, thereby reducing the fin members located around the parts of the pipe protruding from the plate, on the whole resulting in lost surface of heat transmission in the remaining parts of the pipe.

The present invention with surface-enlarging porous air pervious blocks around pipes protruding from plates, such as being described herein, provides for equal surface- enlargement in all directions of the pipe. Furthermore, the pipe may be given a zigzag-shaped radial extension along and transversally the rotating plate. Plural changes of direction provide for further benefits as regards the heat transmission inside the pipe. From thermodynamic laws, it is known that a change of direction for a fluid inside a pipe involves enhanced heat transmission between the fluid and the pipe wall. By means of the present invention, this is utilized such that the heat transmission in the pipe becomes more effective, as compared to the technique according to the above-mentioned GB 1 435 435 where complex pipe shapes cannot be used.

The invention is not limited to the various described and shown embodiments, but variations thereof are naturally possible within the scope of claim 1.

Claims

1. A cooling device comprising a rotating, part (1) provided with an internal space (3) intended for the transport of cooling liquid and provided with external fins (4) intended for the transport of gas along at least a section of the rotating part (1), wherein the rotating part (1) is designed symmetrical in rotation around an axis of rotation (2), and comprises a cooling liquid pump section (5), a fan section (β), and between these an intermediate section (7) arranged around the axis of rotation (2), where the fan section (6) has a basic shape of a radially extended plate (15) , wherein the flow of cooling liquid in use enters at the pump section (5) from an object to be cooled, proceeds through the intermediate section (7) and turns back in the vicinity of the periphery (17) of the fan section (6), in order to once again pass the intermediate section (7) and then be pumped back to the object by means of the pump section (5) , characterized in that a number of blocks arranged in rotational symmetry or a circular section (20) of an air pervious material having favourable heat exchanging properties, such as a sintered material of copper, aluminium or Carbon Graphite Foam or a conductive plastic material, are arranged radially inside regular fan fins (4) .

2. A cooling device according to claim 1, in which the external fins (4) are arranged radially and deflecting towards the plate (15) at an angle to the axis of rotation (2) .

3. A cooling device according to claim 1, in which the plate (15) has a corrugated shape.

4. A cooling device according to any of claims 1-3, wherein said blocks or circular section have/has an axially inclined shape in relation to the radial extension of the cooling device.

5. A cooling device according to any of claims 1-4, wherein cooling liquid channels are formed in said blocks or circular section, such that at least a part of said cooling liquid flow can run through the blocks or circular section.

6. A cooling device according to claim 5, wherein the cooling liquid channels are formed as pipes or cavities in the air pervious material having a plurality of changes of direction for enhanced heat transmission.

7. A cooling device according to claim 6, wherein said pipes have a zigzag form extending radially along and transversally to said plate.

8. A cooling device according to any of claims 1-7, wherein air channels are arranged in the air pervious material with smooth changes of direction in order to allow any occurring particles of dust to pass.