Heat exchanger.

The present invention concerns a heat exchanger.

In particular, it concerns a heat exchanger that is compact and portable, onto which a tube and a head are connected to quickly cool or heat a mass or element.

It is already known that heat exchangers exist which make use of a compressor and a fluid for heating or cooling an element.

A disadvantage thereof is that such heat exchangers are usually large and heavy, as a result of which they are difficult to move.

The present invention aims to remedy one or several of the above-mentioned and other disadvantages.

To this end, the present invention concerns a heat exchanger which is composed of a base plate, several cooling fins and accumulator blocks, whereby the cooling fins are fixed to the base plate and the accumulator blocks are pressed in the base plate or provided therein, whereby the base plate and cooling fins are made of a first metal alloy, and the accumulator blocks are made of a second metal alloy whereby the second metal alloy provides for a better heat conduction than the first metal alloy.

An advantage of a heat exchanger according to the invention

is that the heat exchanger is cheaper and lighter than an embodiment that would be entirely made of the second metal alloy.

As a result, the heat exchanger can easily form a part of a compact device with which heat can be quickly transferred.

This is for example important to quickly warm up the muscles of sportsmen/women and athletes. It restricts the time that is required to treat the sportsmen/women while their muscles are nevertheless sufficiently warmed up.

A second example is that a device according to the invention can also be used for certain patient treatments, offering the advantage that the treatment is speeded up and will be more efficient.

In a preferred embodiment of a heat exchanger according to the invention, the heat exchanger is screwed down to a strut through which a fluid is guided via a tubular element.

Such a strut is known for example from patent BE 2006/0232.

A treatment head with a tube is preferably coupled to the heat exchanger according to the invention, whereby the head comprises two feed-through elements, such that a good heat transfer is obtained and a closed liquid circuit is realised with the heat exchanger.

An advantage of a heat exchanger according to the preferred

embodiment of the invention is that a relatively small amount of liquid must be led through the heat exchanger for a certain volume of heat transfer.

In order .to better explain the characteristics of the invention, the following preferred embodiments of a heat exchanger according to the invention are described by way of example only, without being limitative in any way, with reference to the accompanying drawings, in which:

figure 1 schematically represents a heat exchanger according to the invention, seen in perspective; figures 2 and 3 are sections of figure 1 according to lines II-II and III-III respectively; figure 4 shows a preferred embodiment of a heat exchanger according to the invention; figure 5 shows the construction of the above-mentioned embodiment from figure 4 ; figure 6 shows a preferred embodiment of the heat exchanger, coupled to a treatment head; figures 7 up to 13 included show details of the treatment.

Figure 1 shows a heat exchanger 1 according to the invention which is provided with a base plate 2 and cooling fins 3.

The base plate 2 and cooling fins 3 are preferably made of aluminium, and the cooling fins 3 are glued to the base plate 3.

Figure 1 also shows how the base plate is provided with grooves 4 in which the cooling fins 3 are arranged for more lateral rigidity. Some of the outer cooling fins are hereby partly cut out on either side of the angles situated at the top and at the front .

Figures 2 and 3 show how accumulator blocks 6 are pressed in the bottom of the base plate 2, whereby the accumulator blocks 6 are made of a material which provides for a better heat conduction than the material out of which the base block 2 and the cooling fins 3 are made.

The accumulator blocks 6 are preferably made of copper or a copper alloy, and the base plate 2 and cooling fins 3 of aluminium or an aluminium alloy.

It should be noted that the accumulator blocks 6 must not necessarily be pressed in the base plate 2, but it is probably more appropriate in order to obtain a more durable heat exchanger 1 according to the invention, since a copper alloy is more difficult to process than an aluminium alloy, which can be easily glued.

Figure 4 shows a preferred embodiment of a heat exchanger 1 according to the invention whereby the heat exchanger 1 is contained in a cover plate 8 which is screwed down on the base plate 2 by means of screws 9. The cover plate 8 hereby runs in the longitudinal direction together with the cooling fins 3. At the front, the heat exchanger 1 is covered with a fan module 10 placed crosswise onto the cooling fins 3.

On either side, at the bottom of the cover plate 2, are fixed side plates 11 under which is provided a frame 12. This frame is provided with crosswise holes 13 and 14.

Figure 5 shows the assembly of a heat exchanger 1 according to figure 4 and it shows how the base plate 2, on the lower side where the accumulator blocks 6 are situated, is screwed down to a strut 15 through which a fluid is led by two (or several) tubular elements 16.

Such a strut 15 is disclosed in patent BE 2006/0232. For the sake of completeness, it should be mentioned that such a strut 15 has a predominantly U-shaped cross section with a back wall on which is each time provided a protruding leg on two opposite edges, which legs are provided with a cross collar on their free edges extending to the outside of the U-shaped strut, whereby the outside of the back wall is entirely or almost entirely flat, and whereby the strut 15 is provided with a tubular element 16 on its open side, made in one piece with the strut 15 and extending parallel to the legs.

An advantage of such a strut 15 is that it can be extruded and, consequently, it can be made in many different sizes and in an economical manner.

Figure 5 also shows how little chunks 17 are provided in the angles 5 where the recesses of the cooling fins 3 are situated, such that the fan module 10 can be screwed down on them by means of screws 9.

The assembly is completed with a U-shaped pipe 18 which connects the two elements 16 of the strut 15 to one another. Apart from that, bushes 19 and rings 20 are used to guide the screws 9 of different lengths through.

The use of a heat exchanger 1 according to the invention is simple and as follows.

Figures 1 to 3 included show that the essence of the heat exchanger 1 consists of the use of accumulator blocks 6 which make contact with a base plate 2 and cooling fins 3. Since the accumulator blocks 6 conduct the heat better than the base plate 2 and cooling fins 3, they can be made more compact so as to remove the required amount of heat.

Rs mentioned above, the accumulator blocks 6 are preferably- made of copper or a copper alloy, and the base plate 2 and cooling fins 3 of aluminium or an aluminium alloy.

Thus is obtained a heat exchanger 1 which combines the good heat conductivity of the copper alloy with the lighter weight and the lower cost price of an aluminium alloy in order to obtain a light and compact device which can quickly remove a required amount of heat.

In order to obtain a heat transfer over the accumulator blocks 6 that is as large as possible, the latter are made as smooth as possible, since roughness has a negative effect on the heat transfer. The blocks 6 might for example be polished to an average maximal roughness height

of 4 m.

The working of a preferred embodiment of the heat exchanger 1 to be used in such a device which is not shown in the figures can be best explained by means of figures 4 and 5.

If one wishes to cool an element quickly, a circuit with a cooling liquid can be led through the heat exchanger 1 via the feed hole 13. The tubular elements 16 of the strut 15 will then give off the heat to the accumulator blocks 6 which in turn will transfer the heat to the base plate 2 and the cooling fins 3. The produced heat is sucked in by the fan module 10 and blown into the atmosphere. The U- shaped pipe 18 makes sure that the cooling liquid is led via a loop formed of two tubular elements 16 in the case of the present figure, and that the heat is transferred to two accumulator blocks 6.

The cooling liquid then leaves the heat exchanger 1 via the outlet 14. To this outlet 14 can be coupled a tube or a pipe having a treatment head at its far end. This is appropriate for the physiotherapy treatment of sportsmen/women and patients.

The heat exchanger 1 may also work with a closed liquid circuit for the physiotherapy treatment of sportsmen/women, as is schematically shown in figure 6.

The treatment head 21 is then connected to the heat exchanger 1 by means of a tube 22.

Figure 7 shows how the treatment head 21 is formed of a head or a tip 23, a body 24 and a connecting piece 25. In the body are provided a small feed-through element 26 and a large feed-through element 27. Optionally, also a Peltier element 28 could be provided in the body 24.

By connecting this Peltier element 28 to a power source, the heat transfer or the cooling power can be accurately adjusted and the thermal expansions of the feed-through elements 26 and 27 can be absorbed.

Figures 8 and 9 show how the small feed-through element 26 is provided at the back with a preferably cylindrical, wider part 29 which changes in a preferably cylindrical, narrow part 30 towards the front, i.e. to the tip side of the treatment head 21. The wider part 29 is provided with outside thread 31 on its (casing) surface. The small feed- through element 26 also has a supply opening 32 and a return opening 33. Optionally, additional holes 34 may be provided which may possibly serve for the use of screws.

Figure 10 shows how the large feed-through element 27 is provided with a preferably cylindrical, narrow part 35 which changes in a preferably cylindrical, wider part 36 towards the front, i.e. towards the tip side of the treatment head 21. The narrow part 35 is hollow and provided with internal thread 37 extending over a certain length at the back in the cavity 38, i.e. on the side of the connecting piece 25 of the treatment head 21. Additional holes 39 may be optionally provided in the wider part 36, which may possibly serve to fix screws in.

The cross sections as shown in figures 11, 12 and 13 show that the dimensions of the small feed-through element 26 and the large feed-through element 27 are such that the diameter of the wider part 29 of the small feed-through element 26 is practically equal to the inner diameter of the narrow part 35 of the large feed-through element 27, such that the outer thread 31 of the small feed-through element 26 can mesh with the inner thread 37 of the large feed-through element 27 and both feed-through elements 26 and 27 fit into one another.

The cavity 38 of the large feed-through element 27 is preferably provided with a stop 40 which can be used for the wider part 29 of the small feed-through element 26. In the part of the cavity 38 which is screened by the stop 40 towards the tip side is preferably provided a second internal thread 41.

Preferably, the height of the ribs of the above-mentioned second screw thread 41 is such that the inner diameter of this part of the cavity 38 is practically as large or somewhat larger than the external diameter of the narrow part 30 of the small feed-through element 26.

Figures 6 and 13 show how, when the feed-through elements 26 and 27 are screwed together and are provided in the treatment head 21, a closed liquid circuit is created together with the heat exchanger 1. Arrow A in figure 6 shows how the cooling liquid leaves the housing of the heat exchanger 1 via the outlet opening 14 and flows to the

large feed-through element 27 via the supply opening 32 according to arrow C via the supply duct 22A of the tube 22 according to arrows A ¹ and A' ' . The inner thread 41 is preferably made such that the cooling liquid flows between the ribs of the inner thread 41 and follows the helical line towards the tip side of the treatment head 21.

As the cavity 38 at the stop 40 has an inner diameter which is almost equal to the outer diameter of the narrow part 30 of the small feed-through element 26, an immediate flow- back is avoided and an efficient flow of the cooling liquid to the tip side according to arrow C is obtained.

Via the return opening 33, the cooling liquid is driven according to arrow B ¹¹ from the large feed-through element 27 to the return duct 22B of the tube 22 and thus to the inlet 13 of the frame 12 of the heat exchanger 1.

An advantage of the above-described embodiment of the treatment head 21 is that, thanks to the large contact surface over and between the ribs of the inner thread 41, a more efficient heat transfer is obtained.

The feed-through elements 26 and 27 and the tip 23 are preferably made of aluminium or brass or another material which provides a good compromise between a good transfer of heat and a light weight.

Compared to a traditional treatment head, the above- described embodiment of a heat exchanger 1 with a treatment head 21 aims to cool down from 40° to 2 ⁰ C in one minute and

a half; with a traditional treatment head, this would take three minutes. When treating tennis players, for example, for whom only 90 seconds of treatment is allowed between two games of a match, the physiotherapy treatment of spasms will be far more efficient.

It is clear that the heat exchanger 1 with a treatment head 27 can be realised according to many different embodiments without departing from the principle of the invention.

Thus, it is clear that a strut 15 may have several pairs of tubular elements 16 which connect at the top with several pairs of accumulator blocks 6 and have U-shaped pipes 18 on alternating sides, such that the cooling liquid is led several times over the heat exchanger 1. There will be several inlets 13 and outlets 14 then, of which at least one inlet 13 can be connected to a return duct 22B and at least one outlet 14 can be connected to a supply duct 22A of a tube 22.

It is also clear that the heat exchanger can be used to quickly heat a liquid whereby the heat transfer then takes place in the opposite sense from the one described above.

As a practical example of a heat exchanger 1 according to the invention to be used for the treatment of sportsmen/women and patients, we think of a device weighing less than 10 kg, preferably less than 5 kg and even better still less than 3 kg, whereby it uses ^ litre of cooling liquid in the latter case in order to be able to treat sportsmen/women for some ten minutes and patients for some

20 to 30 minutes. The cover plate 8 hereby has a length of some 25 cm and the lower frame measures some 20 by 20 cm. This device replaces a compressor weighing 30 kg and which consequently is difficult to move. A device according to the invention, however, is compact and can be easily carried, such that a sportsman/woman can for example be treated on the sports field itself instead of in a practice.

Optionally, sensors are provided in the frame 12 to measure the temperatures for different positions within the heat exchanger 1 or to measure how much cooling liquid is flowing through the heat exchanger 1. It is clear that additional options may be provided.

It should be noted that in the above description, the longitudinal and cross direction, the front and rear side and the upper and lower side specifically refer to the drawings for simplicity's sake, but it is clear that they depend on the position of the observer and that they do not restrict the essence of the invention in any way.

The present invention is by no means restricted to the embodiments described above and represented in the accompanying drawings; on the contrary, a massive cardboard heat exchanger according to the invention can be made in all sorts of ways while still remaining within the scope of the invention.