DESCRIPTION

Technical field

The present invention relates to a system for hydraulically and electrically connecting a plurality of heated ducts configured for carrying an electrically heatable fluid.

Background art

In the field of electrically heated ducts a need is felt for providing connection systems for connecting such ducts wherein both the electric heating and the hydraulic connection of the latter are preserved. This need is particularly, but non exclusively, perceived in selective catalytic reduction applications (typically indicated and abbreviated as "SCR") for abating NOXs (nitrogen oxides) in exhaust gases. SCR devices are used in industrial combustion applications and also in internal combustion engines of motor vehicles. The reaction that makes it possible to transform urea and nitrogen oxides into water and C02 is effected by spraying the urea solution onto a catalyst, and is strongly temperature-dependent. In order to comply with the increasingly stringent regulations concerning the emissions of diesel vehicles, it is necessary to position the catalyst in a region where the exhaust gases are still hot, typically on the diesel particulate filter or immediately downstream of the same. In this position, however, the catalyst temperature may exceed the optimal value, resulting in decreased efficiency in abating NOXs. For this reason, in the latest systems there is a double injection of water-urea solution, typically onto the catalyst and downstream of the silencer .

One example of such an application is provided by international patent application publication WO 2019/038652 A1 in the name of the present Applicant.

Summary of the invention

It is one object of the present invention to provide a system for hydraulically and electrically connecting a plurality of ducts configured for carrying a heatable fluid, such a system being improved over those made in accordance with the prior art. In particular, this system provides easier and more reliable assembling.

This object is achieved through a system comprising the technical features mentioned in the appended independent claim. Some optional and preferred technical features of such a connector are set out in dependent claims.

It is understood that the appended claims are an integral part of the technical teachings provided in the following detailed description of the present invention. In particular, the appended dependent claims define some preferred embodiments of the present invention that include some optional technical features.

Further technical features and advantages of the present invention will become apparent in light of the following detailed description, provided herein merely by way of non-limiting example, wherein reference will be made to the annexed drawings, which are summarized below.

Brief description of the drawings

Figure 1 is a perspective view of a system for hydraulically and electrically connecting a plurality of ducts configured for carrying an electrically heatable fluid. Such system is made in accordance with an illustrative embodiment of the present invention.

Figure 2 is a further partial perspective view of the system of Figure 1 from a different perspective, wherein the protective case of said system is not shown. Figure 2 also shows the system during an intermediate step of the process of assembling the system.

Figures 3 and 4 are perspective views of a supporting assembly configured to support and house electric heating means included in the system. In these figures, the supporting assembly is shown in an open condition. In particular, Figure 3 shows that part of the supporting assembly which operationally faces inwards when the assembly is in a closed condition; Figure 4 shows that part of the supporting assembly which faces outwards when the assembly is in a closed condition.

Figure 5 is a partial perspective view of a portion of the supporting assembly when applied to the hydraulic connection assembly. In this figure one can see the electric connections between the electric heating means of the heated ducts and the heating means of the hydraulic connection assembly .

Figure 6 is a partial perspective view of the system, showing the hydraulic connection assembly without the supporting assembly.

Figure 7 is a perspective view of a further variant embodiment of the system shown in the preceding figures, wherein the protective case is formed by coupling two half shells .

Detailed description of the present invention

With particular reference to Figures 1 and 2, reference numeral 10 designates as a whole a system for hydraulically and electrically connecting a plurality of ducts configured for carrying an electrically heatable fluid. Such system is made in accordance with an exemplary embodiment of the present invention.

As a non-limiting example of the present invention, system 10 is particularly suitable for connecting ducts for SCR devices in motor vehicles.

System 10 is configured for providing hydraulic and electric connections for a plurality of heated ducts 12. In the illustrated embodiment, heated ducts 12 are three, but in further variants of the present invention such ducts may be two or even more than three.

With particular reference to Figure 2, heated ducts 12 are configured for carrying an electrically heatable fluid. In particular, each one of heated ducts 12 comprises a tubular element 14 in which the fluid is intended to flow. Moreover, each one of heated ducts 12 comprises one or more electric heating cables 16 arranged (e.g. wound) around tubular element 14, which heat up the fluid as it flows through tubular element 14. In particular, tubular element 14 is preferably coated with a protective sheath 13, e.g. a corrugated tube (as shown in Figure 7) or a co-extruded tube (as shown in figure 1) .

With particular reference to Figure 6, system 10 comprises a hydraulic connection assembly 18 made of thermally conductive material. Assembly 18 comprises a plurality of unions 20. Each one of unions 20 is configured to be hydraulically connected to one of heated ducts 12. Furthermore, connection assembly 18 comprises an intermediate hollow body 22 into which unions 20 terminate, configured to be crossed by the fluid flowing in heated ducts 12.

System 10 comprises also one or more electric heating wires 24 configured to heat up connection assembly 18. Electric heating wires 24 of system 10 extend along hydraulic connection assembly 18 and are configured to be electrically connected to electric heating cables 16 of heated ducts 12 through an electric connection 26, e.g. effected by means of electric connectors 50 and 52.

System 10 further comprises a covering case 28 fixed to hydraulic connection assembly 18 so as to cover electric heating wires 24 and the electric connectors 26.

System 10 comprises also a supporting assembly 30 configured to support and house electric heating wires 24 and electric connections 26. The supporting assembly comprises a pair of half-shells 32, 34 configured to be mounted in a mutually closable manner on connection assembly 18. Furthermore, supporting assembly 30 has one or more seats 38 within at least one of half-shells 32, 34, which internally house at least one tract of the respective electric heating wires 24, keeping them in contact with connection assembly 18.

Thanks to the above-mentioned measures, hydraulic connection assembly 18 can be heated just like heated ducts 12 by exploiting the electric power supplied to heated ducts 12. Moreover, the structure of supporting assembly 30 is so conceived that tracts of electric heating wires 24 are pre assembled in seats 38 formed in half-shells 32, 34. This facilitates the assembling of system 10 because, in particular, it makes it easier to move supporting assembly 30 and install it on hydraulic connection assembly 18. In fact, seats 38 carrying heating wires 24 allow for an orderly and stable arrangement of the latter, without the operator having the worry about them getting twisted or mutually entangled while moving supporting assembly 30 and installing it on hydraulic connection assembly 18. After said installation, electric heating wires 24 are electrically connected in a through manner to electric heating cables 16 of ducts 12, thus effecting electric connections 26.

Preferably, supporting assembly 30 has one or more clip portions 36 outside at least one of half-shells 32, 34, configured for holding electric connectors 26.

It should be noted that clip portions 36 may have different shapes and dimensions depending on the construction technology thereof (e.g. injection moulding or additive manufacturing) and on the type of electric connection 26 to be housed therein. In this regard, for example, in Figure 2 clip portions 36 have a "C" shape within which electric connection 26 is housed by snap or pressure coupling; whereas Figures 4 and 5 illustrate a variant wherein such clip portions 36 consist of pairs of substantially straight plates substantially parallel to each other, which define an interstice into which electric connection 26 is inserted by snap or pressure coupling.

Preferably, half-shells 32, 34 are constrained to each other; in particular, they are made as one piece. Such half shells 32 and 34 are movable between an open condition (Figures 3 and 4) , in which they are mutually spaced apart, and a closed condition (Figure 2), in which they are coupled together, enclosing intermediate hollow body 22 and at least a part of unions 20 making up hydraulic connection assembly 18. Even more preferably, half-shells 32, 34 are mutually rotatable about an axis of rotation X-X. In the illustrated embodiment, the axis of rotation X-X is obtained from a weakened region 40 of supporting assembly 30 situated between half-shells 32, 34. For example, weakened region 40 is a thinner portion of supporting assembly 30 and is situated substantially along an axis of symmetry of supporting assembly 30, consisting of said axis of rotation X-X.

In the illustrated embodiment, wherein three heated ducts 12 are mutually connected by hydraulic connection assembly 18, supporting assembly 30 is substantially shaped as a double T, wherein each one of half-shells 32, 34 forms a T intended to be superimposed on the T defined by the other one of half-shells 32, 34. Each branch of the T defined by respective half-shell 32, 34 has a substantially semicylindrical shape and it is so designed as to cover, in addition to intermediate hollow body 22 and unions 20, also a proximal region of tubular element 14.

Preferably, half-shells 32, 34 are provided with snap coupling means configured to allow such half-shells 32, 34 to mutually lock into the closed condition. By way of example, the locking means comprise one or more protrusions 42 carried by one half-shell 32 and one or more respective holes 44 in the other half-shell 34. Protrusions 42 and holes 44 are configured to be coupled together by interference during the mutual insertion operation, when half-shells 32, 34 are brought one against the other into the closed condition .

Preferably, seats 38 are provided as grooves 46 formed within half-shells 32, 34 and configured to internally house tracts of electric heating wires 24. Grooves 46 are made in the form of tracks or recesses along the inner surface of half-shells 32, 34, in which electric heating wires 24 can be inserted. The extension of grooves 46 is substantially longitudinal, in particular substantially parallel to the sides of the T's defined by half-shells 32, 34.

Preferably, the tracts of electric heating wires 24 enter and/or come out of grooves 46 via through openings 48 in half-shells 32, 34. This ensures contact between electric heating wires 24 and hydraulic connection assembly 18, in order to ensure the heat exchange necessary for heating up the fluid.

In the illustrated embodiment, each one of grooves 46 receives the respective tract of electric heating wire 24 through one of through openings 48, situated at one end of groove 46; also, each one of such grooves 46 leads the respective tract of electric heating wire 24 out through another one of through openings 48, situated at the opposite end of groove 46.

Preferably, as better visible in Figure 5, each one of electric connections 26 is effected through the coupling between a male connector 50 and a female connector 52. In particular, one of connectors 50, 52 is carried by a respective electric heating cable 16, and the other one of connectors 50, 52 is carried by the corresponding electric heating wire 24. Conveniently, also the electric connections between electric heating cables 16 of heated ducts 12 can be effected in the same manner, i.e. through a connection between a male connector 50 and a female connector 52; conveniently, such connections can be housed in respective clip portions 36 of supporting assembly 30.

In the illustrated embodiment, electric connection 26 comprises an electrically insulating sleeve 54 wound around it. Advantageously, sleeve 54 has a wider cross-section in an intermediate position, which can facilitate the centering thereof in clip portion 36.

Preferably, sleeve 54 is made of heat-shrinking material. Preferably, inside sleeve 54 there is an adhesive adapted to ensure protection of the electric connection against liquid infiltrations after shrinking. In particular, the use of connectors 50, 52, whereon sleeve 54 is then applied, makes system 10 easier to assemble, because it is easier for the operator to handle the wiring and fasten it in an orderly manner to supporting assembly 30.

In the embodiment illustrated in Figure 1, covering case 28 is made by overmoulding after inserting hydraulic connection assembly 18 and supporting assembly 30 into a mould. Nevertheless, covering case 28 may also be made by mutually coupling a pair of elements 28a, 28b, e.g. of the half-shell or shell type, at the periphery thereof, as shown also in the variant illustrated in Figure 7.

In the illustrated embodiment, hydraulic connection assembly 18 advantageously comprises, on its outer surface, a protrusion 56 configured to be coupled to a matching recess (not visible in the drawings) and situated on the surface of supporting assembly 30 operationally facing inwards. The shape of the recess matches the shape of protrusion 56, so as to form a coupling mechanism or mode of the so-called "poka-yoke" type between hydraulic connection assembly 18 and supporting assembly 39, thus preventing any mistakes when assembling the system and forcing the operator to mount the components with the correct orientation. For example, protrusion 56 is situated outside a position of angular intersection between two of unions 20.

Conveniently, supporting assembly 30, and in particular at least one of half-shells 32 and/or 34, is provided with appendices 58 configured to permit a reproducible positioning of said supporting assembly 30 in the mould prior to overmoulding case 28 (embodiment shown in Figure 1), so as to reduce the movement thereof during the injection of the material. In other words, appendices 58 are configured to hold supporting assembly 30 in a predetermined position as it is inserted into an overmoulding mould and during the next step of overmoulding the protective case in the mould.

As an alternative, such appendices 58 may be used for correctly positioning supporting assembly 30 on protective case 28 (variant shown in Figure 7), which is then assembled over it. More generally, appendices 58 are configured to hold supporting assembly 30 in a predetermined position, by coupling with and fitting into corresponding portions having a matching shape formed in protective case 30.

In light of the above, in more general terms, appendices 58 are configured to constrain supporting assembly 30 to protective case 28 in a predetermined position.

In the embodiment illustrated in the variant of Figure 7, also such appendices 58 provide a "poka-yoke" mode for assembling together case 28 and supporting assembly 30 (in turn assembled on hydraulic connection assembly 18) .

Preferably, appendices 58 are provided in the form of tips, in particular situated at the top of the plates forming clip portions 36.

Of course, without prejudice to the principle of the present invention, the embodiments and implementation details described and illustrated herein merely by way of non-limiting example may be subject to numerous changes without however departing from the scope of the invention as set out in the appended claims.