FLUID HEATING DEVICE

Abstract

 A heating device for heating a fluid, comprising a heating element (1), a first dissipating element (2) and a first casing (4), having a substantially tubular shape, which encloses said first dissipating element (2) and, at least partially, said heating element (1), said first dissipating element (2), said heating element (1) and said first casing (4) being positioned so that said first dissipating element (2), substantially shaped as an helicoid and placed around said heating element (1), is in contact with said heating element (1) and with said first casing (4) so that they define a first channeling path for the fluid to be heated by means of the heat produced by the heating element (1), characterized in that said dissipating element (2) is built integrally, or in one piece, with said heating element (1).

Description

[0001] The present invention relates to a fluid heater.

[0002] More specifically, the present invention relates to a heat exchanger adapted to heat a fluid that passes close to a heating element.

[0003] A device of this type normally includes a resistor, or resistive element, positioned in a tubular casing.

[0004] Such casing may be made of thermally conductive or insulating material according to the use envisaged, connected to a power circuit.

[0005] Alternatively, dual-wall heating devices may be provided, wherein two tubular casings (and therefore two respective resistors) are arranged coaxially one inside the other.

[0006] Exchangers of this type provide for a fluid to be heated to flow close to the electric resistor, in which a potential difference is established.

[0007] It produces heat due to the Joule effect, which heat is yielded, through suitable exchange and/or containment walls, to the inlet fluid, which has a greater temperature at the outlet thereof.

[0008] The difference in temperature therefore depends on a series of factors, for example the power developed by the resistor, the properties of the fluid and/or of the materials forming the exchange walls and the sizes thereof and speed with which the fluid crosses the exchanger.

[0009] However, due to construction or usage needs of the device, it often is not possible to obtain an optimal energy balance in the operation of the device. Indeed for example, in the case of device having particularly contained sizes, it may be necessary to cause the resistor to generate very high powers as a consequence of the reduced exchange surfaces available, so as to make available sufficient heat to heat the fluid to an adequate temperature.

[0010] This inevitably results in the system not operating in an optimal manner, in particular considering the following aspects:

• due to construction reasons and to the features of the materials and fluids used, not all the heat generated by the resistor is able to be transmitted to the fluid, thus creating dissipation problems of the excess quantity, which is greater the higher the power at which the resistor operates;
• the overall energy efficiency remains low due to the consistent portions of energy used and dispersed.

[0011] Problems of this type become very significant in light of the fact that there often is a need to make devices of the type described, with suitable features in terms of design compactness and design ease.

[0012] It therefore is the aim of the invention to provide a fluid heating device which simultaneously is efficient and effective.

[0013] It is another aim of the invention at hand to make a heating device which ensures an adequate heating of the fluid also at levels of power that are not particularly high.

[0014] If is a further aim of the invention to provide a heating device which combines a compact, easy-to-make design with the above-mentioned advantages.

[0015] These and other aims are attained by a fluid heating device according to appended claim 1, and by a method according to appended claim 9.

[0016] Further technical features are indicated in the appended dependent claims. Other aims and advantages will more fully emerge from the description that follows, relative to a preferred embodiment thereof given by way of nonlimiting example, of the heating device, which is the object of the present invention, and from the appended drawings, in which:

• Figure 1 is a side view of a first embodiment of the fluid heating device according to the invention;
• Figure 2 is a front view of the embodiment shown in figure 1;
• Figure 3 is a top view of the embodiment shown in figures 1 and 2;
• Figure 4 shows the cross section along the line IV-IV in Figure 1;
• Figure 5 is a cross section of a second embodiment of the fluid heating device according to the invention.

[0017] With particular reference to Figures 1 to 3, they show a fluid heating device 100, which heating element 1 in the case described is a cartridge resistor enclosed by a casing.

[0018] The heating element 1 is for example, substantially cylindrical-shaped and may have, at an end thereof, pins 11 for connection to the electric source, fastening means (not shown), e.g. screws, and also sensors, e.g. temperature control sensors (they also not shown).

[0019] It is also enveloped by a first dissipating element 2, preferably shaped as a helicoid, for example consisting of a metal coil.

[0020] A first substantially tubular-shaped casing 4 entirely encloses the first dissipating element 2 and at least partially the heating element 1.

[0021] A second dissipating element 21 and a second casing 3 are arranged externally to the first casing 4 in order to at least partially envelop the casing 4, in a coaxial arrangement.

[0022] The first casing 4 has an open end, the one covered by the second casing 3, and a closed end, to allow the circulation of the fluid therein.

[0023] Both ends of the second casing 3 are closed.

[0024] A first outlet valve 51 for the fluid is on the first casing 4, while a second inlet valve 50 is obtained on the second casing 3.

[0025] As shown in the cross section of Figure 4, the dissipating elements 2 and 21 are constructed so that the coils thereof adhere respectively to the walls of the heating element 1 and of the first casing 4, and to the ones of the first casing 4 and of the second casing 3; therefore, the elements 2 and 21 may serve a function of thermal bridge for transmitting heat by conduction, not only to the circulating fluid but also between the casings 4 and 3 themselves. In order to illustrate in greater detail, the dissipating element 2 is in contact with the internal surface of the first casing 4 and with the external surface of the heating element 1; when present, the dissipating element 21 is in contact with the internal surface of the second casing 3 and with the external surface of the first casing 4: thereby, a structurally simple and above-all efficient path for channelling the fluid is created between inlet and outlet between the walls of the heating element 1 and of the first casing 4 and in the same way between the walls of the first casing 4 and of the second casing 3.

[0026] The fluid inlet from valve 50 indeed initially runs through the coil comprised in the gap identified by the two casings 3 and 4 (in the direction shown by arrows A in Figure 1).

[0027] A pre-heating of the fluid itself occurs in this portion due to the heat from the most inner section wherein the fluid is in direct contact with the heating element 1, which therefore has an increased temperature.

[0028] Following the direction of arrow B, the fluid is channelled into the gap comprised between the first casing 4 and the heating element 1, running through it in opposite direction to the first gap, towards the outlet valve 51 (arrow C).

[0029] Therefore, the dissipating elements 2, 21, together with the casings 3, 4, are also part of the hydraulic circuit.

[0030] Advantageously, the casing 3 maintains the second dissipating element 21 made in a coil in compression, which in turn ensures the fact that both the first dissipating element 2 and the casing 4 remain in contact and in position on the heating element 1, thus creating a reliable and at the same time, functional system.

[0031] A further peculiar feature of the device described is the fact that the portion of the first casing 4 not covered by the second casing 3 may be modulated as a function of the general optimization of the system and of the temperature desired for the outlet fluid. The greater the surface covered by the casing 3, the more the system decreases the quantity of heat dispersed, thus gaining in energy efficiency. In a further variant, if the second casing 3 and the second dissipating element 21 are not required, i.e. if the device may function in adequate manner also in the absence of such components, both ends of the first casing 4 are closed and the inlet valve 50 of the fluid is obtained thereon.

[0032] In the second embodiment of the fluid heating device, whose section is shown in figure 5, the heating element 1 also incorporates the dissipating element 2, which is built integrally with the heating element 1 itself.

[0033] A.

[0034] In this embodiment, the dissipating element 2 has also a helical or spiral shape, in order to direct the flow of fluid to be heated according to arrows A.

[0035] This design solution eliminates the separation interface between elements 1 and 2, with two main advantages.

[0036] Heat transmission is much more efficient because there is no wall effect at the junction, which can possibly occur in the first embodiment.

[0037] In addition, the thermal exchange surface between the fluid and heating element 1 is thus increased, since in the first embodiment the dissipating element 2 was in turn heated by the heating element, whereas in this case it transfers heat directly to the fluid.

[0038] It is apparent that in addition to resolving the drawbacks mentioned above, in light of the construction and operating simplicity, a device of the type described has intrinsic features of versatility in use and of affordability which are apparent with respect to the prior art.

[0039] The features of the fluid heating device, the object of the present invention, clearly emerge from the preceding description, as do the advantages thereof.

[0040] It is also apparent that the invention is described by way of example only, without limiting the scope of application, according to its preferred embodiments, but it shall be understood that the invention may be modified and/or adapted by an expert in the field without thereby departing from the scope of the inventive concept of the claims herein.

Claims

1. Heating device for heating a fluid, comprising a heating element (1), a first dissipating element (2) and a first casing (4), having a substantially tubular shape, which encloses said first dissipating element (2) and, at least partially, said heating element (1), said first dissipating element (2), said heating element (1) and said first casing (4) being positioned so that said first dissipating element (2), substantially shaped as an helicoid and placed around said heating element (1), is in contact with said heating element (1) and with said first casing (4) so that they define a first channeling path for the fluid to be heated by means of the heat produced by the heating element (1), characterized in that said dissipating element (2) is built integrally, or in one piece, with said heating element (1).

2. Heating device (100) according to claim 1, characterized in that said first casing (4) is provided with one open end.

3. Heating device (100) according to at least one of the previous claims, characterized in that said first casing (4) is enclosed, at least partially, by a second casing (3).

4. Heating device (100) according to at least one of the previous claims, characterized in comprising a second dissipating element (21), substantially shaped as an helicoid, placed around said first casing (4) and enclosed by said second casing (3), and positioned so that it is in contact with said first casing (4) and with said second casing (3) so that they define a second channeling path for said fluid.

5. Heating device (100) according to claim 4, characterized in that said second dissipating element (2) is in contact with an internal surface of said second casing (3) and is built integrally, or in one piece, with an external surface of said first casing (4).

6. Heating device (100) according to at least one of the previous claims, characterized in comprising an outlet valve (51) and an inlet valve (50), respectively to allow the exit and the entrance of the fluid to be heated, wherein at least one between said outlet valve (51) and said inlet valve (50) is placed on said first casing (4).

7. Heating device (100) according to claim 6, characterized in that said outlet valve (50) and said inlet valve (50) are placed respectively on said first casing (4) and on said second casing (3).

8. Heating device (100), according to at least one of the previous claims, characterized in that said heating element (1) is a cartridge resistor.

9. Method for producing a heating device (100) according to any one of the previous claims 1-8, comprising a mechanical processing step to produce said dissipating element (2) integrally, or in one piece, with said heating element (1).

Drawing