[0001] The present invention concerns the field of cooling techniques using a cooling fluid.
[0002] In particular, the present invention concerns the cooling techniques that use cooling
oil to cool electrical devices like, for example, power and distribution electrical
transformers. In greater detail, the present invention concerns an oil or fluid radiator
in general, in particular for cooling devices of the above mentioned type.
STATE OF THE ART
[0003] Different types of radiators are known in the art for cooling electrical devices
like transformers and similar devices.
[0004] A first type of radiators is constituted by panel radiators. These radiators essentially
comprise one or more panels, each obtained by joining (for example, welding) two metallic
half-shells at the level of their edges. Each one of the half-shells is obtained by
cutting a portion of sheet having a suitable length from a coil, as well as by pressing
each portion of sheet in such a way as to give it the desired shape, essentially the
shape of a half-shell. The number of panels can obviously vary depending on the required
performance, in particular depending on the desired heat dissipation. Obviously, during
use, the two opposite ends of each panel are connected respectively to a delivery
manifold and to a discharge or outlet manifold, wherein the delivery and discharge
manifolds are mutually connected respectively by means of a main delivery and discharge
manifold. The cooling oil coming from the transformer thus circulates by natural convection
between the two opposite ends of each panel and transfers heat towards the outside
through the metal.
[0005] A second type of radiators is constituted by the so-called tubular radiators. In
this case, each radiator is produced by using tubular units (for example, made of
carbon steel) and assembling them in such a way as to form individual elements made
up of a plurality of tubular units. The tubes or tubular units of each element are
connected through a delivery cap and a return cap respectively connected (for example,
welded) at the opposite ends of each single tube of the element, as well as by connecting
the delivery caps through a delivery manifold and the return caps through a return
manifold. In this way, the cooling oil coming from the transformer flows into the
delivery caps through the manifold and then reaches the return caps through the single
tubes, successively flowing out of the radiator through the return or outlet manifold.
[0006] The radiators of the known type described above, even if useful for several types
of applications, however entail several drawbacks that can be summed up as follows.
[0007] A first inconvenience or drawback of panel radiators regards their efficiency (in
terms of heat dissipation), which is rather limited, especially in the case of radiators
characterized by a high number of panels and/or panels positioned very near each other.
Substantially, in these cases the heat dissipated by a panel is at least partially
reabsorbed by the adjacent panel. The direct consequence of this reduced efficiency
is that for a particular application (for example, for cooling an electrical transformer)
it is necessary to increase the number of panels (however, in this case dissipation
efficiency is further reduced) and/or the dimensions of the same. In this last case,
however, problems arise that are due to the increase in weight and make the radiator
difficult to handle during both transport and operation.
[0008] The known panel radiators have also a structural problem, in fact they are made in
such a way that they do not include lowered portions (elements that make it possible
to place the flange of the inlet or delivery manifold at a lower height compared to
the inlet manifold itself) larger than 400-500mm.
[0009] In fact, the technicians in charge with sizing the radiators for a transformer always
plan to interface with the transformer tank with a distance between centers that is
not always the same as that of the radiator. The tank, in fact, sometimes allows for
coupling distances between centers that are much smaller than the optimal dimension
for radiators, a dimension that must be studied taking in consideration the thermal
misalignment between the active part of the transformer and the thermal center of
gravity of the radiators.
[0010] Therefore, the radiator has the first two or three elements lowered to the maximum
dimension allowed by the size of the transformer tank, while the other elements that
make up the entire radiator are raised in order to better exploit the radiator by
increasing oil circulation in a natural convection regime (the higher the thermal
misalignment, the faster the oil flow and the better the heat dissipation obtained,
as the so-called "hydronic load" determined by the fluid density variation caused
by the temperature variation is higher).
[0011] Regarding radiators of the type with panels, a further problem that characterizes
them derives from the fact that they cannot be tested under pressures exceeding 2-2.5
bars. In fact, higher pressures deform the piece. Technical specifications (for example,
the TERNA specification) are already available that set testing pressures at 350kPa
(3,5Bar), therefore these specifications exclude the use of panel radiators.
[0012] With regard to tubular radiators, instead, these have a heat dissipation efficiency
that is even 30% higher than that of panel radiators; furthermore, they make it possible
to face structural problems in a more proper manner (it is possible to make portions
lowered even by 1000-1100mm) and they resist even testing pressures of 9 bars.
[0013] On the other hand, tubular radiators are penalized by a quality/cost ratio that sometimes
leads users to prefer panel radiators even if they offer lower performance levels.
In fact, the welding and assembly technology used to make tubular radiators is certainly
more expensive than the welding technology used to make panel radiators, which are
much simpler to weld and manufacture.
[0014] Finally, the radiators of both types, if made of iron, have problems related to resistance
to corrosion that make them unsuitable for cooling power and/or distribution electrical
transformers located (as it often happens) in places with varying and more or less
aggressive environmental conditions (classified according to standard EN ISO 12944-2).
Therefore, protection systems are required that should be provided with coatings (painted
and if necessary zinc-plated) having increasingly important and expensive final thicknesses
in economic and even environmental terms. For example, for a class C5M application
- marine environment with a high content of salts - nominal thicknesses equal to 320
um are required.
[0015] Finally, there are often size and transport problems that, both during transport
and disassembly of the radiators from the transformer and in the site where the transformer
is used, make it necessary to resort to solutions with complex layouts due, in fact,
to the considerable volume occupied by the cooling system of the transformer.
[0017] It is therefore one object of the present invention to overcome the drawbacks mentioned
above and observed in the known radiators of the state of the art. In particular,
the aims and objects of the present invention can be summed up as follows.
[0018] It is a first object of the present invention to reduce or at least limit the final
cost of the radiator.
[0019] The second aim or object of the present invention is to improve the radiator's resistance
to corrosion, reducing the quantity of paint to be used with benefits in terms of
environmental protection and in terms of production time and thus of offer to the
user.
[0020] A further object of the present invention is to considerably reduce the overall dimensions
of the entire cooling system (including the radiator), offering the user the opportunity
to solve the increasingly frequent problems related to the space available for the
installation of transformers.
[0021] It is another object of the present invention to considerably simplify the logistic
aspects, especially regarding the transport of transformers and of their cooling system,
with consequent reductions in transport costs.
[0022] It is another object of the present invention to produce a system that from the thermal
point of view is capable of reducing the inertia of the transformer system, reducing
the transient at the level of the voltage peaks and consequently reducing the localized
temperature increase, in particular at the level of the windings, allowing on the
contrary an extension of the transformer's useful life (reduced dilatations, mechanical
stress, losses due to the Joule effect).
[0023] Finally, a direct consequence of the aspects described above is the reduction of
the overall quantity of oil that is necessary, with evident advantages in terms of
direct costs emerging during production, but also indirect environmental advantages
that can be noticed successively in relation with decommissioning and/or oil regeneration
operations.
[0024] The aims and objects mentioned and described above are achieved by means of a radiator
suited to cool, for example, electrical transformers as claimed in claim 1. Further
advantages will also be obtained by means of the further embodiments of the present
invention defined in the dependent claims.
DESCRIPTION OF THE PRESENT INVENTION
[0025] The present invention can be particularly and conveniently applied in the field of
cooling systems for electrical devices and/or equipment, for example power and distribution
electrical transformers. Therefore, this is the reason why examples of application
of the radiator according to the invention to the specific field of cooling system
for electrical transformers are described and/or mentioned here below.
[0026] It should however be noted that the possible applications of the radiator according
to the present invention are not limited to the specific case of electrical transformers
or devices in general.
[0027] On the contrary, the present invention can advantageously be applied to all those
cases in which the user wishes to cool a system generating passive heat by means of
a cooling fluid.
[0028] The present invention is based on the general concept that the drawbacks or disadvantages
that are typical of the solutions known in the art (in particular of both panel and
tubular radiators according to the known art) can be overcome or at least minimized
by making a tubular radiator in which the radiating surface of the tubular elements
is increased compared to that of traditional tubular elements with substantially elliptical
cross section. In particular, according to the present invention, the radiating and/or
heat exchange surface of the tubular elements can be conveniently increased (thus
improving dissipation efficiency) by properly modifying the cross section of the tubular
elements. In greater detail, the present invention intends to provide the tubular
elements (at least one of them) with external longitudinal ribs or fins.
[0029] The present invention is based on a further consideration according to which heat
dissipation can be increased by using aluminium and/or aluminium-based light alloys
to make the tubular components. In fact, since aluminium is characterized by high
heat conductivity, the heat of the cooling fluid inside the tubes will be effectively
dissipated, especially owing to the presence of the ribs or fins mentioned above.
[0030] Furthermore, the present invention is based on the further consideration according
to which by making the tubular elements from section bars (for example, in extruded
aluminium) the problems (at least part, if not all of them) related to logistic aspects,
overall dimensions, weight, economic aspects of the radiators of the known type can
be overcome or at least reduced; furthermore the radiator's resistance to corrosion
will be increased, so that it will be possible to avoid the painting and/or zinc-plating
operations that otherwise would be necessary, for example in the case of iron radiators.
[0031] Based on the considerations expressed above, the present invention comprises a radiator
element according to claim 1. Preferably, said at least one component is made of aluminium
or an aluminium alloy or in any case a material with heat conductivity exceeding 100
W/m K.
[0032] Still preferably, said at least one component is constituted by a portion of an extruded
section bar with predefined length.
[0033] According to the invention, said at least one component can have a substantially
elliptical cross section.
[0034] According to a further variant embodiment of the invention, said radiator comprises
a plurality of said components.
[0035] Preferably, said components are divided into groups made up of a predefined number
of said components, the components of each single group being in communication with
one another through a first delivery cap and a second return cap that are respectively
in communication with the opposite ends of each one of said components, the delivery
caps of each group being in communication with each other through a delivery manifold,
the return caps of each group being in communication with each other through a return
manifold.
[0036] Still preferably, at least one of said main external ribs of said at least one tubular
component has a substantially oval ring-shaped cross section.
[0037] According to a further variant and/or embodiment, at least one of said main external
ribs of said at least one tubular component comprises a plurality of secondary external
ribs that extend from the outer surface of said at least one main external rib.
[0038] According to a further variant, said at least one main external rib of said at least
one tubular component comprises two secondary external ribs that extend from the free
end of said at least one main rib opposite said tubular component in such a way as
to form a predefined internal angle.
[0039] If necessary, said at least one main external rib of said at least one tubular component
may comprise two secondary external ribs that respectively extend from the opposite
outer surfaces of said at least one main rib.
[0040] Again, according to the invention, two internal ribs respectively project from opposing
portions of the inner surface of said at least one component. Said at least two external
ribs respectively extend from the opposing vertices of said at least one tubular component
with elliptical cross section.
[0041] Alternatively, at least one of said internal ribs can extend between opposite portions
of the inner surface of said at least one tubular component and/or the free ends of
the secondary external ribs of said at least one tubular component that extend from
at least one of the opposing outer surfaces of said component with substantially elliptical
cross section may respectively lie on a plane that is parallel to the main plane of
symmetry of said at least one tubular component. Finally, further embodiments of the
invention are defined in the dependent claims.
[0042] The invention also concerns a preferably oil-cooled electrical transformer comprising
a radiator element, wherein said radiator element is constructed according to the
description provided above and/or the concepts claimed below.
BRIEF DESCRIPTION OF THE DRAWINGS
[0043] The present invention is illustrated here below through the following description
of some of its embodiments represented in the attached drawings. It should however
be noted that the present invention is not limited to the embodiments represented
in the drawings; on the contrary, the purpose and the scope of the present invention
include all those variants or modifications of the embodiments represented and described
herein that will result to be clear, obvious and immediate to the expert in the art.
In particular, in the attached drawings:
- Figures 1 and 2 show perspective views of a radiator according to an embodiment of
the present invention;
- Figure 3 shows a perspective view of a detail of the radiator according to an embodiment
of the present invention;
- Figure 4 shows an exploded view of a radiator according to an embodiment of the present
invention;
- Figures 5, 6, 7, 8, 9 and 10 show sectional views of a tubular component of the radiator
according to corresponding embodiments of the present invention.
DETAILED DESCRIPTION OF SOME EMBODIMENTS OF THE PRESENT INVENTION
[0044] In Figures 1 and 2 the radiator according to the present invention is identified
by reference number 100. In particular, the radiator 100 comprises a plurality of
tubes or tubular components 101, each one of which is suited to contain a cooling
fluid (generally a cooling oil) and to allow said fluid to circulate inside it, essentially
from one end to the opposite end. The tubular components 101, in particular, are placed
in fluid-dynamic connection with one another through a plurality of upper caps 102
and lower caps 103, as well as through an upper manifold 104 and a lower manifold
105. In greater detail, the tubular components 101 (in total in the number of one
hundred and eight, but the total number can obviously vary according to the needs
and/or circumstances) are divided into groups or elements, each element or group comprising
a predefined number of tubular components 101 (equal to nine in the example represented
herein, but also in this case the number of tubular components making up each group
can vary according to the needs and/or circumstances). For each group of tubular components
101 there are an upper or delivery cap 102 and a lower or return cap 103. An end portion
of each tubular component 101 is housed in the delivery cap 102, while the opposite
end portion of the same tubular component 101 is housed in the return cap 103. It
can thus be inferred that the cooling fluid flowing into the delivery cap 102 will
reach the return cap 103 through the tubular components 101 that, in fact, are respectively
connected to the delivery cap 102 and the return cap 103. Furthermore, the delivery
caps 102 are mutually connected through a delivery manifold 104, while the return
caps 103 are mutually connected through a return manifold 105. It can thus be inferred
that the cooling fluid flowing in through the delivery manifold 104 will be distributed
among the various delivery caps 102 and from there, through the tubular components
101, will reach the return caps 103, from which it will exit through the return manifold
105. For the connection of the delivery manifold 104 to the main cooling system there
is a connection flange 106, while a connection flange 107 allows connection to the
same main system of the return manifold 105. While a detailed description of the main
system mentioned above is omitted for the sake of brevity, it should be noted that
said main system will be such as to allow the cooling fluid to capture or absorb the
passive heat emitted, for example, by an electrical device (in particular, by an electrical
transformer) so that the absorbed heat will be transferred and dissipated towards
the outside through the radiator 100.
[0045] Figures 1 and 2 show also a hook or ring 108 for lifting and handling the radiator
100, as well as a valve 109 arranged on the delivery manifold 104 and a valve 110
arranged on the return manifold 105. The valve 109 can serve, for example, to allow
the outflow of air bubbles from the radiator, bubbles that would hinder the circulation
of the cooling fluid, or even to allow the fluid to be topped up, while the lower
valve 110 can serve to empty the radiator 110.
[0046] From the detail shown in Figure 3 it is possible to observe a first important characteristic
of the radiator according to the present invention, meaning the fact that the tubular
components 101 (described in greater detail below with reference to other figures)
are provided with longitudinal ribs or fins suited to increase the radiating and/or
heat exchange surface of each tubular component 101. In this way, it is possible to
increase the dissipation efficiency of the radiator.
[0047] The exploded view of Figure 4 makes it possible to observe some important details
of the radiator 100. In particular, it can be inferred from Figure 4 that each one
of the delivery caps 102 is formed by two opposite half-shells 102s and 102d that
are joined in such a way as to form a hollow element, and in particular in such a
way as to define housing seats, each one having a shape corresponding to that of the
cross section of a tubular component 101. In this way, as already mentioned, the end
portion of a tubular component 101 can be accommodated in the housing seat of the
cap 102 defined by the two opposite and joined half-shells 102s and 102d. Furthermore,
each one of the two half-shells 102s and 102d comprises a portion, substantially in
the shape of a semicircle, suited to accommodate the upper manifold 104. In particular,
also the upper manifold 104 is formed by two opposite half-shells, of which only the
half-shell 104s is shown in the figure. The mutual connection of the delivery caps
102 is thus obtained by arranging the two opposite half-shells of the manifold so
as to define a substantially tubular element, and by arranging them in the semicircular
seats provided in the caps. Obviously, the tightness of the radiator, intended to
avoid cooling fluid leakages, can be obtained by means of several solutions among
those known in the art, for example by welding, glueing, etc. the various component
parts. Said solutions do not fall within the scope of the present invention, therefore
their detailed description is omitted for the sake of brevity. The explanation provided
above in relation to the upper or delivery caps 102 and the upper or delivery manifold
104 obviously applies also to the return caps 103 and the return manifold 105.
[0048] Among the materials suited to be used to make the radiator 100 according to the present
invention, aluminium and/or aluminium-based light alloys are certainly worth mentioning.
In particular, the materials with heat conductivity exceeding 100W/m K have proven
to be among the most suitable ones. Aluminium, in fact, is characterized by high heat
conductivity and therefore it is particularly suitable for making the tubular components
101 that, as will be explained below, can be conveniently produced by cutting portions
of section bars, for example extruded section bars, having predefined length. In the
same way, aluminium and/or light alloys can be used to make the caps 102, 103 and/or
the manifolds 104 and 105, as aluminium is particularly advantageous when used to
make the half-shells of both the caps and the manifolds. Obviously, using aluminium
and/or light alloys means obtaining clear advantages in terms of weight reduction
and/or limitation. As already mentioned, Figure 5 illustrates a very important characteristic
of the radiator according to the present invention; Figure 5, in fact, shows a cross
sectional view of one of the tubular components 101 of the radiator. Said tubular
component 101 has a substantially elliptical cross section, meaning that it has two
opposite curved portions joined to each other at the level of two opposite vertices.
The tube 101 with substantially elliptical cross section thus defines an inner volume
V suited to contain a cooling fluid (for example, oil) and to allow said fluid to
circulate inside it (substantially from one end to the other of the tube 101 and thus
perpendicularly to the plane of Figure 5). Main external ribs 120 extend from the
outer surface of the tubular component 101, in particular from the outer surface of
each one of the opposite curved portions of the tube 101, in a substantially perpendicular
direction with respect to the plane of symmetry P of the main body, with substantially
elliptical cross section, of the tube 101. Each one of said external ribs or fins
120 has substantially the shape of an oval ring (in cross section and thus parallel
to the plane of the figure), with two portions of the outer plane and parallel surface
joined by an end curved portion. It can thus be understood that, thanks to the presence
of the main external ribs 120, the radiating surface of the tubular component 101
will be increased, and consequently the dissipation efficiency of the component 101
will also be improved. Obviously, the number, shape and location of the main external
ribs, as well as their dimensions (length perpendicular to the plane P and width parallel
to the plane P) may vary according to the needs and/or circumstances as well as to
the special applications for which the radiator can be intended. For example, the
oval ring shape (in cross section) of the ribs 120 may vary, as it is also possible
to have ribs in a different shape on the same component 101. The location of the ribs
and their mutual distance may also vary, as it is possible, for example, to have ribs
that extend forming an angle different from a straight angle with respect to the plane
P, as well as ribs 120 that extend towards the outside at the level of or in proximity
to the vertices of the main body with substantially elliptical cross section.
[0049] Figure 5 shows also two internal ribs 121 that extend from the inner surface of the
component 101, each at the level of one of the vertices of the ellipse and substantially
having the aim to increase the rigidity of the component 101. It should be noted that
in the embodiment shown in Figure 5 the ends of the ribs 120 extending from the outer
surface of one of the curved portions of the component 101 lie on a plane P1, while
the ends of the ribs that extend from the outer surface of the other curved portion
(opposite the first one) lie on a plane P2 parallel to the plane P1, the planes P1
and P2 thus being parallel to the plane of symmetry P of the tube 101.
[0050] There are thus two factors that according to the present invention make it possible
to improve the dissipation efficiency of the radiator, and precisely the presence
of the external longitudinal ribs or fins (where the word longitudinal means that
the ribs or fins or tabs extend in a direction parallel to the longitudinal extension
of the tubular component), as well as the possible use of aluminium or an aluminium-based
alloy to make the tubular components 101, which improves heat transmission from the
cooling fluid to the tubular component 101. Furthermore, the use of aluminium makes
it possible to employ portions of section bars, for example extruded section bars,
with predefined length, with obvious advantages in terms of simplified radiator assembly
operations and at limited prices. In practice, it will be sufficient to cut portions
of section bars with predefined length and to assemble them together with the caps
and the manifolds, as previously described.
[0051] In Figure 3 it is also possible to observe that the longitudinal extension of the
external ribs or fins 120 is smaller than the overall extension of the tubular component
101; in fact, it can be understood from Figure 3 that the ribs 120 are present only
on the centre portion of each tubular component 101, while they are absent at the
level of the end portions. In this way, the end portions of the tubular component
101 can be housed more easily in the respective delivery cap 102 and return cap 103.
Obviously, in the case of manufacture of the tubular components by cutting portions
of a section bar with predefined length it will be necessary to remove the ribs or
fins 120 at the level of the ends of each portion, an operation that on the other
hand can be easily carried out through known solutions, like for example milling or
similar operations.
[0052] In the embodiment shown in Figure 6 (in which component parts already described above
with reference to other figures are identified by the same reference numbers), the
difference with respect to the embodiment shown in Figure 5 is given by the shape
of the two opposite internal ribs 121 that in this case extend more markedly towards
the inside of the tubular component 101 respectively from its two opposite vertices.
In this case, the two ribs 121, in addition to increasing the rigidity of the tubular
component 101, make it also possible to increase the inner surface of the tubular
component 101 in contact with the cooling oil, with evident advantages in terms of
improved heat transmission from the oil to the component 101, and thus of heat dissipation
from the component 101 towards the outside. Obviously, also in this case, the shape,
size and location of the internal ribs may vary according to the needs and circumstances.
[0053] A further embodiment of the present invention is shown in Figure 7, in which, as
usual, component parts or characteristics that have already been described above with
reference to other figures are identified by the same reference numbers. In this case,
the tubular component 101 comprises a plurality of further internal ribs 122 in addition
to the internal ribs 121 that extend towards the inside, each from one of the two
vertices of the tubular component 101 with substantially elliptical cross section.
In particular, the internal ribs 122 extend from the opposite inner surfaces of the
two curved portions 100 of the tubular component 101, respectively. Increasing the
number of the internal ribs, as well as changing their shape, size and location, if
necessary, means further increasing the inner surface of the tubular component 101
in contact with the cooling fluid and thus heat transmission from the cooling fluid
to the tubular component, with consequent heat dissipation towards the outside thanks
to the heat conductivity of the material and to the external ribs 120 described above.
[0054] The solution adopted according to the further embodiment of the invention illustrated
in Figure 8 makes it possible to further improve heat dissipation from the tubular
component 101 towards the outside. In this case, in fact, each one of the main external
ribs 120 (one or more of them depending on the needs and/or circumstances) is provided
with secondary external ribs 123 (in variable number, size and shape) that extend
from the outer plane and opposite surfaces of the main rib 120 in a direction that
is substantially perpendicular to the longitudinal extension of the main external
rib 120, and thus substantially parallel to the plane of symmetry of the tubular component
101 with substantially elliptical cross section. Obviously, also the direction according
to which the secondary external ribs or fins 123 extend may vary according to the
needs and/or circumstances. For example, Figure 10 shows a particular embodiment,
in which each one of the main external ribs 120 (one or more of them) comprises two
secondary ribs 125 extending from the free end (opposite the main body of the tubular
component 101) of the rib 120 according to predefined angles, in particular in such
a way that the cross section of the rib 120 is substantially Y-shaped.
[0055] According to a further embodiment of the invention shown in Figure 9, the tubular
component 101 is provided with internal ribs 124 that extend between the two opposite
inner surfaces respectively of the two curved portions of the main body of the tubular
component 101, said ribs, if necessary, being connected to each other, for example,
as shown in Figure 9, through a connection or coupling portion substantially parallel
to the longitudinal axis of symmetry of the tubular component 101.
[0056] It has thus been shown through the above description that the radiator according
to the present invention makes it possible to overcome or at least minimize the drawbacks
of the radiators according to the known art, and thus to achieve the set objects.
In particular, the radiator according to the present invention will be characterized
by high dissipation efficiency (thanks to the internal and/or external ribs or fins
of the tubular components) and even thanks to the fact that the tubular components
are made of aluminium or an aluminium-based alloy. The radiator according to the present
invention can furthermore be assembled through simple and inexpensive operations,
in particular in the case where the tubular components are obtained from section bars
(for example, extruded section bars) by cutting portions with predefined length. Moreover,
the radiator according to the present invention will be characterized by high resistance
to corrosion as well as by reduced or limited weight and overall dimensions.
[0057] Obviously, even if the radiator according to the present invention has been illustrated
through the description of its embodiments shown in the figures, the present invention
is not limited to the embodiments described herein and shown in the figures. For example,
it will be clear for the experts in the art that the solutions described herein and
illustrated in the drawings can be changed and/or combined with one another; for example,
while the external ribs or fins 120 and 123 are shown in Figure 8 in combination with
the internal ribs 121, all the possible shapes, sizes and locations of the internal
ribs 121 can be combined with the external ribs 120 and 123 of Figure 8. In the same
way, all the possible external ribs described herein can be combined with one or more
of the solutions provided for the internal ribs.
[0058] Finally, according to an embodiment not illustrated in the figures, the external
ribs or fins can be at least partially hollow, meaning that each of them can be such
as to define an inner volume that communicates with the inner volume of the main body
of the tubular component.
[0059] The invention concerns also a preferably oil-cooled electrical transformer comprising
a radiator element, wherein said radiator element is made according to the description
provided above.
[0060] Although the present invention has been illustrated above through the detailed description
of some of its embodiments, shown in the drawings, the present invention is not limited
to the embodiments described above and shown in the drawings; on the contrary, further
variants of the described embodiments fall within the scope of the present invention,
which is defined in the claims expressed below.
1. Radiator element (100), for instance for cooling electrical transformers by means
of a cooling oil, said radiator element (100) comprising at least one tubular component
(101) suited to contain a cooling fluid and to allow said cooling fluid to circulate
between its two opposite ends; said at least one tubular component (101) comprising
a plurality of main external longitudinal ribs (120) with predefined cross section,
projecting from the outer surface of said at least one component (101); said at least
one tubular component (101) comprising two internal ribs (121) with predefined cross
section, projecting from the inner surface of said at least one component (101); said
radiator element (100) being characterized in that said at least one component (101) has a substantially elliptical cross section; and
in that said two internal ribs (121) respectively extend from the opposite vertices of said
at least one tubular component (101) with elliptical cross section.
2. Element according to claim 1, characterized in that said at least one component (101) is made of aluminium or an aluminium alloy or a
material with heat conductivity exceeding 100 W/m K.
3. Element according to any of claims 1 and 2, characterized in that said at least one component (101) is obtained from a portion of a section bar with
predefined length, for instance an extruded section bar.
4. Element according to any of claims from 1 to 3, characterized in that it comprises a plurality of said components (101).
5. Element according to claim 4, characterized in that said components (101) are divided into groups made up of a predefined number of said
components, the components (101) of each single group communicating with one another
through a first delivery cap (102) and a second return cap (103) that respectively
communicate with the opposite ends of each one of said components (101), the delivery
caps (102) of each group being in communication with each other through a delivery
manifold (104), the return caps (103) of each group being in communication with each
other through a return manifold (105).
6. Element according to any of claims from 1 to 5, characterized in that at least one of said main external ribs (120) of said at least one tubular component
(101) has a substantially oval ring-shaped cross section.
7. Element according to any of claims from 1 to 6, characterized in that at least one of said main external ribs (120) of said at least one tubular component
(101) comprises a plurality of secondary external ribs (123, 125) that extend from
the outer surface of said at least one main external rib (120).
8. Element according to claim 7, characterized in that said at least one main external rib (120) of said at least one tubular component
comprises two secondary external ribs (125) that extend from the free end of said
at least one main external rib (120) opposite said tubular component (101) so as to
form a predefined internal angle.
9. Element according to claim 7, characterized in that said at least one main external rib (120) of said at least one tubular component
(101) comprises two secondary external ribs (123) that respectively extend from the
opposite outer surfaces of said at least one main rib (120).
10. Element according to any of the preceding claims, characterized in that at least two of said internal ribs respectively extend from opposite portions of
the inner surface of said at least one component (101).
11. Element according to any of claims from 1 to 10, characterized in that at least one of said internal ribs extends between opposite portions of the inner
surface of said at least one tubular component (101).
12. Element according to any of claims from 1 to 11, characterized in that the free ends of the secondary external ribs (120) of said at least one tubular component
(101) that extend from at least one of the opposite outer surfaces of said component
with substantially elliptical cross section respectively lie on a plane that is parallel
to the main plane of symmetry P of said at least one tubular component (101).
1. Kühlerelement (100), beispielsweise zum Kühlen von Stromtransformatoren mittels eines
Kühlöls, wobei das besagte Kühlerelement (100) wenigstens eine röhrenförmige Komponente
(101) umfasst, die dazu geeignet ist, eine Kühlflüssigkeit zu enthalten und die besagte
Kühlflüssigkeit zwischen ihren zwei entgegengesetzten Enden zirkulieren zu lassen;
wobei die besagte wenigstens eine röhrenförmige Komponente (101) eine Vielzahl länglicher
Haupt-Außenrippen (120) mit vorbestimmtem Querschnitt umfasst, welche aus der äußeren
Oberfläche der besagten, wenigstens einen Komponente (101) herausragen; wobei die
besagte wenigstens eine röhrenförmige Komponente (101) zwei Innenrippen (121) mit
vorbestimmtem Querschnitt umfasst, welche aus der inneren Oberfläche der besagten,
wenigstens einen Komponente (101) herausragen; wobei das besagte Kühlerelement (100)
dadurch gekennzeichnet ist, dass die besagte, wenigstens eine Komponente (101) einen im Wesentlichen elliptischen
Querschnitt aufweist; und dadurch, dass die besagten zwei Innenrippen (121) sich jeweils
von den entgegengesetzten Spitzen der besagten, wenigstens einen röhrenförmigen Komponente
(101) mit elliptischem Querschnitt erstrecken.
2. Element gemäß Patentanspruch 1, dadurch gekennzeichnet, dass die besagte wenigstens eine Komponente (101) aus Aluminium oder einer Aluminiumlegierung
oder einem Material mit Wärmeleitfähigkeit von mehr als 100 W/m K gefertigt ist.
3. Element gemäß eines jeden der Patentansprüche 1 und 2, dadurch gekennzeichnet, dass die besagte, wenigstens eine Komponente (101) aus einem Abschnitt einer Profilstange
von vorbestimmter Länge gewonnen ist, beispielsweise einer stranggepressten Profilstange.
4. Element gemäß eines jeden der Patentansprüche von 1 bis 3, dadurch gekennzeichnet, dass es eine Vielzahl der besagten Komponenten (101) aufweist.
5. Element gemäß Patentanspruch 4, dadurch gekennzeichnet, dass die besagten Komponenten (101) in Gruppen mit einer vorbestimmten Anzahl der besagten
Komponenten unterteilt sind, wobei die Komponenten (101) jeder einzelnen Gruppe über
eine erste Zulaufkappe (102) und eine zweite Rücklaufkappe (103) miteinander kommunizieren,
welche ihrerseits jeweils mit den entgegengesetzten Enden jeder der besagten Komponenten
(101) kommunizieren, wobei die Zulaufkappen (102) jeder Gruppe über einen Zulaufverteiler
(104) miteinander kommunizieren, und wobei die Rücklaufkappen (103) jeder Gruppe über
einen Rücklaufverteiler (105) miteinander kommunizieren.
6. Element gemäß eines jeden der Patentansprüche von 1 bis 5, dadurch gekennzeichnet, dass wenigstens eine der besagten Haupt-Außenrippen (120) der besagten wenigstens einen
röhrenförmigen Komponente (101) einen im Wesentlichen ovalen, ringförmigen Querschnitt
aufweist.
7. Element gemäß eines jeden der Patentansprüche von 1 bis 6, dadurch gekennzeichnet, dass wenigstens eine der besagten Haupt-Außenrippen (120) der besagten wenigstens einen
röhrenförmigen Komponente (101) eine Vielzahl von sekundären Außenrippen (123, 125)
aufweist, die sich von der Außenfläche der besagten, wenigstens einen Haupt-Außenrippe
(120) erstrecken.
8. Element gemäß Patentanspruch 7, dadurch gekennzeichnet, dass die besagte, wenigstens eine Haupt-Außenrippe (120) der besagten wenigstens einen
röhrenförmigen Komponente zwei sekundäre Außenrippen (125) aufweist, die sich von
dem freien Ende der besagten, wenigstens einen Haupt-Außenrippe (120), die der besagten,
röhrenförmigen Komponente (101) entgegengesetzt ist, erstrecken, so dass sie einen
vorbestimmten Innenwinkel bilden.
9. Element gemäß Patentanspruch 7, dadurch gekennzeichnet, dass die besagte, wenigstens eine Haupt-Außenrippe (120) der besagten wenigstens einen
röhrenförmigen Komponente (101) zwei sekundäre Außenrippen (123) aufweist, die sich
jeweils von den entgegengesetzten Außenflächen der wenigstens einen Hauptrippe (120)
erstrecken.
10. Element gemäß eines jeden der vorstehenden Patentansprüche, dadurch gekennzeichnet, dass wenigstens zwei der besagten Innenrippen sich jeweils von entgegengesetzten Abschnitten
der Innenfläche der besagten, wenigstens einen Komponente (101) erstrecken.
11. Element gemäß eines jeden der vorstehenden Patentansprüche von 1 bis 10, dadurch gekennzeichnet, dass wenigstens eine der besagten Innenrippen sich zwischen entgegengesetzten Abschnitten
der Innenfläche der besagten, wenigstens einen röhrenförmigen Komponente (101) erstreckt.
12. Element gemäß eines jeden der Patentansprüche von 1 bis 11, dadurch gekennzeichnet, dass die freien Enden der sekundären Außenrippen (120) der besagten wenigstens einen röhrenförmigen
Komponente (101), die sich von wenigstens einer der entgegengesetzten Außenflächen
der besagten Komponente mit im Wesentlichen elliptischem Querschnitt erstrecken, jeweils
auf einer Ebene liegen, die parallel zur Hauptsymmetrieebene P der besagten, wenigstens
einen röhrenförmigen Komponente (101) liegt.
1. Élément de radiateur (100), par exemple pour le refroidissement de transformateurs
électriques au moyen d'huile de refroidissement, ledit élément de radiateur (100)
comprenant au moins un composant tubulaire (101) apte à contenir un fluide de refroidissement
et à consentir la circulation dudit fluide de refroidissement entre ses deux extrémités
opposées ; ledit au moins un composant tubulaire (101) comprenant une pluralité de
nervures longitudinales extérieures principales (120) avec une section transversale
prédéfinie, saillant de la surface extérieure dudit au moins un composant (101) ;
ledit au moins un composant tubulaire (101) comprenant deux nervures intérieures (121)
avec section transversale prédéfinie, saillant de la surface intérieure dudit au moins
un composant (101) ; ledit élément de radiateur (100) étant caractérisé en ce qu'au moins un composant (101) présente une section transversale essentiellement elliptique
; et en ce que lesdites deux nervures intérieures (121) s'étendent respectivement des sommets opposés
dudit au moins un composant tubulaire (101) avec section transversale elliptique.
2. Élément selon la revendication 1, caractérisé en ce qu'au moins un composant (101) est réalisé en aluminium ou un alliage d'aluminium ou
un matériau avec une conductivité thermique supérieure à 100 W/m K.
3. Élément selon l'une quelconque des revendications 1 et 2, caractérisé en ce que ledit au moins un composant (101) est obtenu d'une portion d'un profilé ayant une
longueur prédéfinie, par exemple un profilé extrudé.
4. Élément selon l'une quelconque des revendications de 1 à 3, caractérisé en ce qu'il comprend une pluralité desdits composants (101).
5. Élément selon la revendication 4, caractérisé en ce que lesdits composants (101) sont divisés en groupes constitués d'un numéro prédéfini
desdits composants, les composants (101) de chaque groupe étant en communication entre
eux au moyen d'un premier capuchon de refoulement (102) et d'un deuxième capuchon
de retour (103) qui communiquent respectivement avec les extrémités opposées de chacun
desdits composants (101), les capuchons de refoulement (102) de chaque groupe étant
en communication entre eux au moyen d'un collecteur de refoulement (104), les capuchons
de retour (103) de chaque groupe étant réciproquement en communication au moyen d'un
collecteur de retour (105).
6. Élément selon l'une quelconque des revendications de 1 à 5, caractérisé en ce qu'au moins une desdites nervures extérieures principales (120) dudit au moins un composant
tubulaire (101) présente un section transversale ayant une forme essentiellement ovale.
7. Élément selon l'une quelconque des revendications de 1 à 6, caractérisé en ce qu'au moins une desdites nervures extérieures principales (120) dudit au moins un composant
tubulaire (101) comprend une pluralité de nervures extérieures secondaires (123, 125)
qui s'étendent de la surface extérieure dudit au moins une nervure extérieure principale
(120).
8. Élément selon la revendication 7, caractérisé en ce que ladite au moins une nervure extérieure principale (120) dudit au moins un composant
tubulaire comprend deux nervures extérieures secondaires (125) qui s'étendent de l'extrémité
libre de ladite au moins une nervure extérieure principale (120) opposée audit composant
tubulaire (101) de façon à former un angle intérieur prédéfini.
9. Élément selon la revendication 7, caractérisé en ce que ladite au moins une nervure extérieure principale (120) dudit au moins un composant
tubulaire (101) comprend deux nervures extérieures secondaires (123) qui s'étendent
respectivement des surfaces extérieures opposées de ladite au moins une nervure principale
(120).
10. Élément selon l'une quelconque des revendications précédentes, caractérisé en ce qu'au moins deux desdites nervures intérieures s'étendent respectivement de portions
opposées de la surface intérieure dudit au moins un composant (101).
11. Élément selon l'une quelconque des revendications de 1 à 10, caractérisé en ce qu'au moins une desdites nervures intérieures s'étend entre des portions opposées de
la surface intérieure dudit au moins un composant tubulaire (101).
12. Élément selon l'une quelconque des revendications de 1 à 11, caractérisé en ce que les extrémités libres des nervures extérieures secondaires (120) dudit au moins un
composant tubulaire (101) qui s'étendent d'au moins une des surfaces extérieures opposées
dudit composant avec section transversale essentiellement elliptique reposent respectivement
sur un plan parallèle au plan principal de symétrie P dudit au moins un composant
tubulaire (101).