EP1563241A2

EP1563241A2 - Heating device comprising a heat exchanger system

Info

Publication number: EP1563241A2
Application number: EP03758380A
Authority: EP
Inventors: Dominique Seguy; Jean-Luc Deloy
Original assignee: Tepeecal S A S; Tepeecal Sas
Current assignee: TEPEECAL PLUS
Priority date: 2002-10-17
Filing date: 2003-10-17
Publication date: 2005-08-17
Also published as: WO2004036135A3; WO2004036135A2; CA2542637A1; EP1411311A1; AU2003274396A1; AU2003274396A8

Abstract

The present invention relates to a heating device adapted for heating a fluid comprising a heat exchanging system (1) having means for passage of at least one fluid (2, 3), a mounting block (6) on which the heat exchanging system (1) is mounted comprising at least one fluid flow inlet (10) of a fluid to be heated, and at least one fluid flow outlet (11) of the same fluid that has been heated and a fluid bypass system (16) arranged between the at least one fluid flow inlet (10) of a fluid to be heated and the at least one fluid flow outlet (11) of the same fluid that has been heated, wherein the fluid bypass system (16) comprises at least one preset fluid flow obstruction means (17) regulating excess fluid flow, in a preset manner, of the fluid to be heated between the at least one fluid flow inlet (10) of a fluid to be heated and the at least one fluid flow outlet (11) of the same fluid that has been heated.

Description

HEATING DEVICE COMPRISING A HEAT EXCHANGER SYSTEM

The present invention relates to the field of heating apparatus or devices, in particular, comprising a heat exchanger system. The invention will be more particularly described and exemplified with respect to a heating device for heating water in a swimming pool.

Currently, domestic swimming pool heating is performed via a hydraulic system using a heat exchanger. There are two methods of implementation of such a system :

- using a tubular heat exchanger, with either an array of tubes or a drum, that is usually made from metal or composite material ; these systems have the advantage of being able to cope with the total volume of fluid to be heated pumped through the system;

- using a plate heat exchanger, whereby the plates are made of titanium or stainless steel, that are enclosed between a mounting block and a cover plate ; these systems can be easily unmounted, serviced, are adaptable and are also very efficient with respect to energy transmission. The disadvantages of the tubular heat exchange system are that they can not be unmounted, are not adaptable, and have very poor heat transmission performance. On the other hand, the disadvantages of the plate heat exchange system are that the dimensions of the conduits formed within the plates for passage of heating fluid and the plate geometries means that it is impossible to handle the totality of the volume of fluid to be heated being pumped through the system. This problem is currently solved by only pumping a small part of the total volume, say 10 to a maximum of 20% thereof, through the heat exchange plates. The rest of the volume of fluid to be heated is bypassed outside of the heat exchange system. The problem with this is that it is necessary for the swimming pool vendor or fitter, and more often than not the local artisan, such as a plumber or mason, or even the buyer, to create, install and set the bypass manually to obtain the maximal flow rate with maximal heat transmission. Such bypasses are generally made of PVC material and connected in parallel to, but outside of the heat exchange unit. This adds to the complexity and bulk of the system as a whole.

US^°5^°575^°329 describes a heat exchange system for motor vehicle oil, that has a bypass system incorporated into it. However, the aim of this patent is to enable the heat exchange system to work at high initial oil pressures, when the viscosity of cold motor vehicle oil decreases heat transfer efficiency, and thereby to limit the reduction of heat transfer efficiency in the heat exchange system alone. The present applicant has sought to overcome the problems and disadvantages of the prior art. Accordingly, it is an object of the present invention to provide a heating device adapted for heating a fluid, and preferably water for a swimming pool, comprising :

- a heat exchanging system having means for passage of at least one fluid ;

- a mounting block on which the heat exchanging system is mounted comprising at least one fluid flow inlet of a fluid to be heated, and at least one fluid flow outlet of the same fluid that has been heated ; and

- a fluid bypass system arranged between the at least one fluid flow inlet of a fluid to be heated and the at least one fluid flow outlet of the same fluid that has been heated,

- wherein the fluid bypass system comprises at least one preset fluid flow obstruction means regulating excess fluid flow, in a preset manner, of the fluid to be heated between the at least one fluid flow inlet of a fluid to be heated and the at least one fluid flow outlet of the same fluid that has been heated. The device of the present invention is particularly adapted to swimming pool heater systems, wherein the pool water is the fluid to be heated, and is transferred through the device by the filtration pump. The pump's general role is to pump the pool water through a filtration device, such as a sand filter, or diatomaceous earth filter, in order to purify and clean the water. The flow rates of such pumps are imposed by the regulations currently in force for such material. For most domestic swimming pool filter pumps, the flow rates are comprised between about 10 to about 25 m³/h. These pumps function discontinuously, and do not therefore provide a continuous supply of pool water to the heating device. The consequence of this is that the heating device of the invention is adapted to obtain a balance of the loss of head between the heat exchange system flow and bypass flow. Most of the known heating devices are only concerned with limiting loss of head, and the corresponding reduction in heat transfer efficiency from the heat exchange system, since the primary objective in the prior systems is to be as efficient as possible in the heat exchange step. In a preferred embodiment of the present invention, the fluid bypass system is a chamber and the at least one preset fluid flow obstruction means is located within the chamber. In another preferred embodiment of the present invention, the fluid bypass system is a chamber housed within the mounting block and the at least one preset fluid flow obstruction means is located within the chamber.

In yet a still more preferred embodiment of the present invention, the fluid bypass system is a chamber formed within the mounting block and the at least one fluid flow obstruction means is located within the chamber. This particular set up is very advantageous in that it reduces the both the size and the weight of the total installation, since the bypass is actually part of the mounting block to which the inlet and outlet of the fluid to be heated are connected. This set up also enables a temperature sensor to be fitted within the chamber, which is connected to a control unit, by any conventional means, such as an electrical, fibre optic or wireless connection, e.g. via radio or light waves. In a particularly preferred embodiment, the temperature sensor may be slipped inside a finger, or be screwed into a screw fitted metallic insert. The temperature sensor can preferably be located at or in the fluid flow inlet that carries the fluid to be heated into the device, whereby in this configuration one improves the performance of the system, since the thermal inertia incumbent in the system is reduced.

The applicant has also advantageously and surprisingly determined that the chamber of the fluid bypass system can be of a general shape that will enable maximum volume throughput of the fluid to be heated without exceeding the mechanical resistance of the material from which it is made due to the pressure caused by the turbulence of the circulating fluid. In particular, the general shape of the chamber, when it is formed or located within the mounting block, is preferably such that the mounting block is still sufficiently mechanically resistant to prevent buckling of the heat exchanging plates when they are mounted and fixed, e.g by screws, to the mounting block. Accordingly, the most preferable shape for the chamber is roughly triangular. In addition, the applicant has determined that it is most advantageous when the chamber has substantially rounded pockets located at at least two of the corners of the triangle, and the third angle is substantially truncated. The reason for this is so that the mounting block, when the chamber is formed or located therein, still retains enough material for it to stand up to the mechanical constraints of the plates that are fixed against it under pressure, e.g. by screwing of a cover plate. According to another preferred embodiment of the invention, the at least one fluid flow obstruction means comprises a wedge, a plate, a baffle, a deflector, a substantially rectangular block, a generally Y-shaped block, a generally T-shaped block, a generally l-shaped block, a tube, a sphere, a cone, and a truncated cone. Most preferably, the fluid flow obstruction means has a generally parallelepiped shape. Preferably, the flow obstruction means is made of a plastic material, but can also be made of metal or any suitably resistant material adapted to the pressures that are generated by the turbulence of the fluid to be heated. Alternatively, the flow obstruction means can even be formed as part of the chamber, and where the latter is formed in the mounting block, as part of the mounting block, for example via molding, cutting, grinding, honing or metal working. Additionally, the flow obstruction means can provide supplementary mechanical support to the mounting block vis- - vis the mechanical constraints of mounting the heat exchanging plates, as discussed above in relation to the shape of the chamber. Where the flow obstruction means is a separate element, it can be fixed to the fluid bypass means using traditional fixing means, such as soldering, screwing, gluing, welding, nailing and the like. It should be borne in mind that the flow obstruction means is preset during manufacture of the heating device to obtain the maximal flow rate with maximal energy transmission, as a function of the volume of fluid to be heated that is going to be pumped through the heating device. As will be readily understood, the term preset used within the context of the present specification indicates that the parameters of the fluid flow obstruction means, such as size, shape, angle with respect to fluid volume flow, displacement volume, surface rugosity, and the like are determined and fixed during manufacture or assembly of the heating device at the manufacturing plant. In this way, the installer, vendor or home user does not have to face the problem of manually setting up a bypass system and fiddling with the setting in the hope of getting it right. Preferably, the at least one fluid flow obstruction means is fixed to the chamber between the at least one fluid flow inlet of a fluid to be heated and the at least one fluid flow outlet of the same fluid that has been heated. The dimensions and number of fluid flow obstruction means are designed to obtain optimal performance, both in terms of energy transmission and reduction of noise, and thus may vary according to the dimensions of the chamber and the volume of fluid to be heated that is being pumped and bypassed through the system. As a general rule however, the height of the fluid flow obstruction means will generally represent about 3/5 to about 4/5 the height of the chamber. Alternatively, and in a particularly preferred embodiment, the at least one fluid flow obstruction means comprises at least one flow passage allowing fluid to flow therethrough from one side of the fluid flow obstruction means to another side of the fluid flow obstruction means. Preferably between two and four flow passages are provided that allow fluid to flow through from one side of the fluid flow obstruction means to another side of the fluid flow obstruction means. By side, it is meant a face of the obstruction means represented as a horizontal plane perpendicular to the axis of vision of a viewer looking at the obstruction means. It will be readily understood by any skilled person that this means that, for example, when the obstruction means is a parallelepiped, the passages extends from one face to another face, preferably the opposite face. Preferably, the at least one fluid flow obstruction means is an integral part of the mounting block, and is located substantially perpendicular to fluid flow across a chamber between the fluid flow inlet and fluid flow outlet. Thus, when the fluid flow obstruction means is integral with the mounting block, the chamber is divided into two parts or halves, a fluid entry half, and a fluid exit half, and the obstruction means comprise at least one passage allowing fluid to flow from the fluid entry half, through the passage to the other side of the obstruction means and into the exit half of the chamber. The number of passages is adapted to the size of swimming pool to be heated, and is preferably between 2 and 4.

The at least one flow passage can be of a suitable shape and diameter to allow optimised flow of the bypassed fluid. Preferably, the at least one passage is circular, but other forms may be used as appropriate, for example, elliptical, frustoconical, square, rectangular, triangular, or other polygonal shapes. Even more preferably, the diameters of the passages will be from about 15 millimeters to 25 millimeters across. The above description serves to provide the skilled person with the information to adapt the heating device to all situations and will be guaranteed to function optimally without the need for human intervention on the bypass, whilst at the same time limiting the size of the equipment to be installed.

In another preferred embodiment, the flow obstruction means can have a smooth or a rough surface, depending on whether it is desired to increase or decrease the effects of turbulence within the fluid bypass means. The mounting block also has an important role in the present invention, since in a particularly preferred embodiment, it has the chamber of the fluid bypass system housed or formed within it. Consequently, the mounting block can be made from a material that can withstand the mechanical constraints, such as pressure, and wear and tear, caused by the turbulence of the pumped fluid flow inside the bypass chamber. Preferably, the mounting block is formed of a single piece of material. More preferably, the mounting block is formed of a composite material. When the material is a composite material, it can comprise, for example, carbon or tungsten or titanium fibres impregnated or surrounded by polymer resins, wherein the fibres can be oriented or not, or even contain multiple layers of different materials, each layer contributing to the overal strength and resistance of the mounting block. Even more preferably, the mounting block is made of a material comprising expanded plastic, moulded plastic, ceramic and/or metal. Suitable plastic materials are ABS, PVC, high impact plastic, high density polypropylene, high density polyethylene, expanded polyurethane or polyamide, polyethylene terephthalate and the like. Similarly, the metals can be chosen from titanium, aluminium, stainless steel, galvanized steel, and the like, and the ceramic material from known high impact resistant ceramics. It is preferred that the mounting block be made of a material that is as light, yet as resistant as possible, and for this reason, expanded plastic materials such as ABS, expanded polyurethane and polyethylene terephthalate are preferred. The latter is particularly preferred due to its excellent properties in wear resistance, hardness and stiffness, continuous operating temperature, mechanical strength, good dimensional stability, weather resistance, chemical resistance and low coefficient of friction. In a most preferred embodiment, the heat exchanging system is in direct contact with the fluid bypass system. In this case, it is also preferable that the chamber of the fluid bypass system be in direct contact with the heat exchanging system, since this will ensure a direct transfer of the fluid to be heated into the heat exchange system, whilst at the same time ensuring an adequate bypass, i.e. optimal functioning of the heating device.

In an alternatively preferred embodiment, the mounting block is provided with at least one reinforcing means for supporting the heat exchanging system. The reinforcing means can preferably be an integral part of the mounting block, or inserted into the mounting block. Most preferably, the reinforcing means are located in the rounded pockets at the corners of the chamber.

In still yet another alternatively preferred embodiment, the heat exchanging system is in indirect contact with the fluid bypass system. With regard to the heat exchanging system used, the invention preferably uses a heat exchanging system based on a set of heat exchange plates, that are formed in such a way that when two or more plates are laid one on top of the other, a heating fluid passageway is formed enabling heating fluid to flow and dissipate its thermal energy to the plates. Such heat exchanging systems are well known in the art, and the plates are often made of stainless or galvanized steel or titanium. The heating fluid provided to the heat exchanging system will generally come from a primary source of heat, such as solar power or a burner powered by gas, petrol, fuel, coke, coal, oil or electricity. Since domestic installations, for which the current inventive device is preferably designed, often use these types of burners, they will readily provide a constant source of primary heat that can be circulated into the heat exchanging system of the heating device of the current invention ir order to provide heat by thermal exchange to the fluid to be heated. The heat exchanging system also provides for passage of the fluid to be heated, but the two fluid sources do not come into direct contact. The fluid to be heated obtains its thermal energy by transfer from the plates that have been heated by the fluid from the primary source of heat. Since the passage for the fluid to be heated is relatively small in diameter and total surface area, the total volume of fluid to be heated being pumped into the heating device can not pass through the heating system. This is why the heating device of the invention is provided with flow bypass means comprising fluid flow obstruction means, to divert fluid to be heated back out of the heating device.

Although the present invention has been described with respect to a heating device for use in heating water in a swimming pool, it is to be understood that such a heat exchanger system and device comprising it can also be used, e.g. for domestic hot water supply requirements, whereby the heat exchange system could be connected to a boiler or gas, coal or oil fired burner that is used for general radiation heating of a building, and the water to be heated for the hot water supply could be pumped through from and back to a storage tank via the heating device of the present invention. The present invention will now be exemplified in more detail through the description of a most preferred embodiment, and making reference to the non-limiting figures in which :

- Figure 1 represents a top side perspective view of part of a preferred heating device of the present invention";

- Figure 2 represents a closer top side view of the same part of the preferred heating device of Figure 1 ^°;

- Figure 3 represents a bottom side view of the same part of the preferred heating device of Figure 1 ^°;

- Figure 4 represents a side view of the preferred heating device of Figure" 1. - Figure 5 represents a most preferred embodiment of the device of the invention seen from a top perspective view.

Detailed Description of the Invention

In Figures 1 to 3, part of a preferred heating device is shown, with the assembled 5 device being represented in Figure 4. The device, which is adapted for heating fluid, comprises a heat exchange system 1 , not shown in Figure 1 but displayed in Figure 4. The heat exchange system 1 comprises one or more heat exchange plates 2, 3, preferably between two and thirty plates. These plates are generally made of stainless or galvanized steel or titanium, since such materials have high resistance to

10 corrosion and relatively high thermal conductivities. The resistance to corrosion is advantageous when the fluid to be heated is water from a swimming pool, since such fluids generally contain corrosive chemical substances that are necessary for microbiological control, such as chlorine and salts, or other oxidative or reductive active species, such as the hypochlorite anion. The heat exchange plates are

15 provided with at least one passageway that allows fluid to flow between the plates. These passageways are not shown in the figures since the kind of plates that are useful in the invention are well known in the art and can be readily acquired in commerce. The plates comprise a passageway for fluid flow of a fluid that is hot, or has a greater thermal energy than the fluid of the swimming pool to be heated. This

$0 hot fluid is typically known as a primary source, and is often generated by a primary source heater means, such as solar power, or a burner, that may be electrically powered, or powered by combustible fuels, such as coke, coal, gas, petrol, fuel and oil. In the case of application of the present invention for use with a domestic swimming pool, the hot fluid can come from the household central heating system.

25 The primary heater source that provides the fluid with greater thermal energy enters and leaves the heat exchange system via an inlet 4 and an outlet 5 respectively, provided in a mounting block 6, on which the heat exchange plates 2, 3 are mounted. These plates 2, 3 are stacked one on top of the other with the aid of plate guides 7, 8 that extend substantially vertically, from the mounting block 6, and have the general

30 shape of a rod. These plate guides can be made of metal, wood or plastic, as long as they are adapted for the application envisaged, but such choice of materials for the guides is within the general knowledge of the skilled person. A cover plate 9 serves to hold down the top heat exchange plate and provide a seal with respect to the fluid passageway provided within the latter. The cover plate 9 can be made of metal, for

35 example the same material as the heat exchange plates, or it can also and more preferably be made of the same material as the mounting block 6. As mentioned previously, the mounting block can be made of metal, such as stainless or galvanized steel or titanium, expanded plastic, moulded plastic, and/or ceramic, but preferably it is made from plastic material, and more preferably from expanded plastic materials, such as expanded polyurethane and ABS, or high impact plastics such as polyethylene terephthalate , since these are relatively light weight and are generally classed as high impact resistant materials. The cover plate 9, heat exchange plates 2, 3 and mounting block 6 are connected in a sealtight manner together by a classical mounting system, comprising for example threaded bolts or rods and corresponding nuts or a clamping system, not shown on the figures, for which bores 12, 13, 14, 15 are provided in the mounting block 6 and the cover plate 9. As mentioned previously, Figures 1 and 2 represent top side perspective views of part of the heating device of the present invention, and in particular the mounting block 6. As can be seen in these figures, the mounting block serves as a base for the plate guides 7, 8, which extend substantially vertically therefrom. The mounting block 6 also comprises at least one fluid flow inlet 10 of a fluid to be heated, and at least one fluid flow outlet 11 of the same fluid that has been heated by the heating device, which in the preferred embodiment is water from a swimming pool. The diameters of inlet 10 and outlet 11 are substantially greater than those of inlet 4 and outlet 5, and as will be apparent from the figures and the arrangement of inlets 4 and 10, and outlets 5 and 11 , the respective hot or high thermal energy fluid circuit and the circuit containing fluid to be heated, i.e. the one bringing water to be heated from the swimming pool, are set counter-current to each other. It has been discovered by the present inventors that this arrangement offers the optimum performance of the heating device with respect to the fluid to be heated.

The device according to the present invention also comprises a fluid bypass system^°16 arranged between the fluid flow inlet 10 of a fluid to be heated and the fluid flow outlet 11 of the same fluid that has been heated after passing through the heat exchange system. The bypass system enables optimisation of the pass through flow rate for the heating device, minimizing thermal energy loss, by redirecting a predetermined flow from the inlet 10 to the outlet 11 , whilst maintaining maximum throughput through the heat exchange system. In order to do this, the fluid bypass system comprises at least one preset fluid flow obstruction means 17 regulating excess fluid flow, in a preset manner, of the fluid to be heated between the at least one fluid flow inlet 10 of a fluid to be heated and the at least one fluid flow outlet 11 of the same fluid that has been heated after passing through the heat exchanging system. In the preferred embodiment illustrated in the figures, particularly figures 1 and 2, the preset fluid flow obstruction means is a parallelepiped shaped block, that is arranged between the inlet 10 and the outlet 11. As has been mentioned previously, this block can be fixed, e.g. via a screw, bolt, nut, glue, etc, or other suitable fixing means 18 (cf. Figure^°4) to the mounting block 6. Alternatively, the fluid flow obstruction means 17 can be formed as part of the mounting block 6, for example by molding. The position of the obstruction means, its size, angle, surface smoothness/rugosity in relation to the incoming and outgoing fluid flows is set during manufacture and assembly of the heating device at the manufacturing facility, as a function of the volume of fluid to be heated, and therefore bypassed, and also as a function of the materials from which the mounting block and the device in general are made. As is apparent from the figures, the fluid bypass system 16 is a chamber 22 and the fluid flow obstruction means 17 is located within the chamber 22, substantially in the midpoint between the inlet 10 and the outlet 11. The chamber 22 is housed, or in the preferred embodiment formed within the mounting block 6, for example when the mounting block 6 is molded from plastic or shaped from metal. The chamber 22 has a generally triangular shape, for this has been demonstrated by the applicant to be the optimal shape capable of dealing with the high mechanical shear generated by the flow of fluid in, and out, of the chamber 22 via the inlet 10 and outlet 11. It is to be noted in this preferred embodiment that the inlet 10 and outlet 11 communicate directly with the chamber 22, through the face opposite to that on which the heat exchange plates 2, 3 are mounted with the aid of the guide rods 7, 8. In this particular embodiment, the heat exchanging plates 2, 3 are also directly mounted on the mounting block 6 and therefor are in direct contact with the chamber 22, and form a peripheral sealtight contact with the latter. As an option, a seal may be provided, for example a silicon rubber torus arranged around the upper peripheral edge of the chamber 22. The generally triangular shape of the chamber 22 described previously is slightly modified in two respects, in that it has a substantially rounded pocket 19, 20 located at at least two of the corners of the triangle, and the third angle 21 is substantially truncated to give a general shape to the chamber that ressembles a clothes hanger without the hook. The rounded pockets 19, 20, which are generally circular, are substantially displaced with respect to the vertex of the triangle that runs parallel to the longitudinal axis of the mounting block 6, whereas the vertices that run to the summit of the truncated angle 21 are substantially tangential to the outer radius of the arc described by the pockets 19, 20. These pockets 19, 20 enable substantial alignment with the passageways formed in the heat exchange plates 2, 3. This enables fluid that is to be heated to flow through the plates 2, 3, by leaving chamber 22 via pocket 20. Once the fluid to be heated has finished its course through the heat exchange plates 2, 3, it will be at a higher temperature than on entry into the heat exchange system, and the fluid that is now heated will exit the heat exchange plates 2,3 and re-enter the chamber 22 via pocket 19, and from there will exit the chamber via outlet 11. In a second and most preferred embodiment, and as illustrated schematically in Figure 5, the device additionally comprises reinforcing means 23, 24, which are located in the rounded pockets19, 20 of the chamber 22 and form an integral part of the mounting block. These reinforcing means 23, 24 can be, for example, inserts that have a generally toric shape, and are inserted into the pockets and held by chemical or mechanical bonding. Alternatively, the reinforcing means can be bridging material that is integral to the material of the mounting block, which means that they can be molded or machined along with the mounting block. The reinforcing means can also have any suitable shape, such as an angle, an arc, a segment, and the like. The role of the reinforcing means 23, 24 is to provide mechanical support for the bottom heat exchange plate of the heat exchanging system. Since such heat exchange plates are generally made of titanium, they tend to be rather flexible, and under the operational conditions of pressure at which the device of the invention operates, this can lead to leakage of heat exchange fluid into the by-pass system containing the fluid to be heated. Since the two circuits are intended to be separate, it is preferable to avoid such an inconvenience by providing the reinforcing means as described.

Additionally, the device contains a fluid obstruction means 17 that extends from one side of the chamber 6 to the other, forming a complete barrier to flow of fluid coming from the fluid inlet 10, and flowing towards the fluid outlet 11. The obstruction means 17 comprises a set of fluid flow passages 25, 26, 27, which allow fluid to flow from one side of the obstruction means to the other, and thereby allowing fluid to by-pass the heat exchanging system in a controlled manner. The number and diameter of the fluid flow passages are determined so that the loss of head between the heat exchange system 1 and the by-pass system 16 is balanced out, i.e. there is substantially no overall loss of head in the device. In Figure 5, three fluid flow passages are shown, but the number can be anything be from one to six, and preferably is from two to four, and most preferably three. In terms of diameter, one can consider that diameters varying from 15 to 25 mm, and preferably 19 to 20 mm, are preferred.

The device functions as follows when used for heating water from a swimming pool: - hot water coming from a primary heat source is introduced into the heat exchange circuit via inlet 4 and runs through the plates 2,3 to exit the heat exchange system via outlet 5 ;

- significantly cooler water, in a larger volume than that of the primary hot water circuit is taken from the swimming pool and introduced into the chamber 22 via inlet 10. It is to be noted that the primary heat source and the cooler water are arranged in counter-current flows to each other, thus enabling optimum efficiency in heat transfer through the heat exchange plates. The obstruction means 17 is of a size, dimension and angle to the incoming cool water flow that it provides resistance, while at the same time letting cool water through which will then mix with water that has been heated leaving the heat exchange system 1 and entering the chamber 22 again. The obstruction means

17 is setup on manufacture to provide the optimum resistance and maximum flow throughput via inlet 10 of the water to be heated through the heat exchange system, which will depend on the volume of the swimming pool water to be heated. The heated water and overflow or bypassed water mix together in the chamber 22 near outlet

11 , before being circulated back into the swimming pool.

The temperature difference between the inlet water and the outlet water can vary between about 0.1 jC and 0.5jC, depending on the power of the heat exchanger, which is in turn adapted in size and volume flow to the to volume of the water reservoir, e.g. swimming pool, to be heated. The power of the heat exchanger also depends partly on the number of heat exchange plates provided, as well as the available heating power of the primary heat source. In general, economical heating of a swimming pool can be achieved with the invention over a period of 4 to 5 days maximum.

It is to be understood that other components can be added to the mounting block 6 and/or the chamber 22, such as, for example, an air-vent, a drainage system, anti- return valves, stop valves and the like. The table below gives details of examples of three devices that can be made according to the present invention, and shows variation in the number and diameter of the fluid flow passages, the corresponding number of heat exchange plates, and flow rates that are attainable with the device of the present invention adapted for use in heating swimming pools :

Table 1

Claims

1 ) Heating device adapted for heating a fluid comprising :

- a heat exchanging system (1 ) having means (2,3) for passage of at least one fluid ; - a mounting block (6) on which the heat exchanging system is mounted comprising at least one fluid flow inlet (10) of a fluid to be heated, and at least one fluid flow outlet (11 ) of the same fluid that has been heated ; and

- a fluid bypass system (16) arranged between the at least one fluid flow inlet (10) of a fluid to be heated and the at least one fluid flow outlet (11) of the same fluid that has been heated,

- wherein the fluid bypass system (16) comprises at least one preset fluid flow obstruction means (17) regulating excess fluid flow, in a preset manner, of the fluid to be heated between the at least one fluid flow inlet (10) of a fluid to be heated and the at least one fluid flow outlet (11 ) of the same fluid that has been heated.

2) Heating device according to claim 1 , wherein the fluid bypass system (16) is a chamber (22) and the at least one fluid flow obstruction means (17) is located within the chamber(22).

3) Heating device according to claim 1 , wherein the fluid bypass system (16) is a chamber (22) housed within the mounting block (6) and the at least one fluid flow obstruction (17) means is located within the chamber (22).

4) Heating device according to claim 1 , wherein the fluid bypass system (16) is a chamber (22) formed within the mounting block (6) and the at least one fluid flow obstruction means (17) is located within the chamber (22). 5) Heating device according to claim 1 , wherein the fluid bypass system (16) is a chamber (22) and the chamber (22) contains a temperature sensor for the fluid to be heated connected to a control unit, preferably located in the fluid flow inlet (10) of a fluid to be heated.

6) Heating device according to claim 1 , wherein the fluid bypass system (16) is a chamber (22) and the chamber (22) is roughly triangular in shape.

7) Heating device according to claim 5, wherein the chamber (22) has a substantially rounded pocket (19, 20) located at at least two of the corners of the triangle, and the third angle is substantially truncated (21 ).

8) Heating device according to claim 1 , wherein the at least one fluid flow obstruction means (17) comprises a wedge, a plate, a baffle, a deflector, a substantially rectangular block, a generally Y-shaped block, a generally T- shaped block, a generally l-shaped block, a tube, a sphere, a cone, and a truncated cone.

9) Heating device according to claim 1 , wherein the at least one fluid flow obstruction means (17) has a generally parallelepiped shape.

10) Heating device according to claim 1 , wherein the at least one fluid flow obstruction means (17) comprises at least one flow passage (25, 26, 27) allowing fluid to flow therethrough from one side of the fluid flow obstruction means (17) to another side of the fluid flow obstruction means (17). 11) Heating device according to claim 1 , wherein the at least one fluid flow obstruction means (17) comprises between two and six , and preferably three, flow passages (25, 26, 27) allowing fluid to flow therethrough from one side of the fluid flow obstruction means (17) to another side of the fluid flow obstruction means (17). 12) Heating device according to claim 1 , wherein the at least one fluid flow obstruction means (17) is an integral part of the mounting block (6), and is located substantially perpendicular to flow of by-passed fluid across a chamber (22) between the fluid flow inlet (10) and the fluid flow outlet (11).

13) Heating device according to claim 12, wherein the at least one fluid flow obstruction means (17)

14) Heating device according to claim 1 , wherein the fluid bypass system (16) is a chamber (22) and the at least one fluid flow obstruction means (17) is fixed to the chamber (22) between the at least one fluid flow inlet (10) of a fluid to be heated and the at least one fluid flow outlet (11 ) of the same fluid that has been heated.

15) Heating device according to claim 1 , wherein the mounting block (6) is formed of a single piece of material.

16) Heating device according to claim 1 , wherein the mounting block (6) is made of a material comprising expanded plastic, moulded plastic, ceramic and/or metal.

17) Heating device according to claim 1 , wherein the mounting block is formed from polyethylene terephthalate.

18) Heating device according to claim 1 , wherein the mounting block (6) is formed of a composite material. 19) Heating device according to claim 1 , wherein the heat exchanging system (1) is in direct contact with the fluid bypass system (16).

20) Heating device according to claim 1 , wherein the heat exchanging system (1 ) is in indirect contact with the fluid bypass system (16).

21) Heating device according to claim 19, wherein the fluid bypass system (16) is a chamber (22) and the chamber (22) is in direct contact with the heat exchanging system (1).

22) Heating device according to claim 1 , wherein the mounting block (6) is provided with at least one reinforcing means (23, 24) for supporting the heat exchanging system. 23) Heating device according to claim 1 , wherein the mounting block (6) is provided with at least one reinforcing means (23, 24) for supporting the heat exchanging system, and the reinforcing means (23, 24) is an integral part of the mounting block (6), or inserted into the mounting block (6).

24) Heating device according to any one of claims 7, 23 and 24, wherein the reinforcing means (23,24) are located in the rounded pockets (19,20).