Patent Publication Number: US-2011073585-A1

Title: Device for Heating a Fluid Transfer Line

Description:
FIELD OF THE INVENTION 
     The present invention concerns a device for heating a fluid transfer line including at least one pipe and at least two pipe connectors mounted at opposite first and second ends of the line. The invention applies notably to a fluid transfer line for automobile vehicles the content of which needs to be heated. 
     BACKGROUND OF THE INVENTION 
     Quick-release connection systems in automobile vehicles generally have the function of connecting fluid transfer pipes to parts of the engine. Many parts of an automobile vehicle must be heated, notably when starting, for reasons of efficiency, pollution and/or passenger comfort. To this end, the pipe, the quick-release connection system or both at once can be heated as required via two separate heating devices, the latter option having the disadvantage of requiring separate electrical connectors for heating the pipe and the connection system and possibly devices for protecting against overheating and/or different automatic regulator devices for the pipe and for the connection system. 
     There may be cited for example the document WO-A2-2008/151924 that teaches helically winding two heating wires along a pipe and disposing the ends of these wires in a quick-release connection system to heat the connector as well. 
     SUMMARY OF THE INVENTION 
     An object of the present invention is to propose a device for heating a fluid transfer line, that line including at least one pipe and at least two pipe connectors to be heated which are mounted at opposite first and second ends of the line, this device eliminating the above drawback and including: 
     said connectors, which include at least one first connector intended to be mounted at said first end and optionally between two consecutive pipes in the case of pipes connected in series and a single second connector intended to be mounted at said second end, 
     at least one pair of metal heating elements (wires, by way of nonlimiting example) which are intended to be disposed along the or each pipe and which are connected to the or each first connector, the pair of heating elements adjacent to said second end being further connected to the second connector, and 
     electrical power supply means configured to power the first connector at said first end. 
     To this end, in a device of the invention, the or each first connector incorporates electrical connection means which are connected to the corresponding pair of heating elements to connect it electrically to the power supply means, and the single second connector incorporates means for closing the electrical circuit formed by the pair or pairs of heating elements and by these connection means, so that the or each pipe heats the corresponding connectors via these connection and closure means. 
     It will be noted that in the device of the invention it is the heating elements disposed along the or each pipe that heat these connection and closure means and thus the corresponding connectors, essentially by thermal conduction and/or by the Joule effect. In this regard, these connection and closure means are produced in an appropriate material to promote this thermal conduction. 
     It will also be noted that the connectors of the device of the invention heated in this way may all be connection inserts or terminals, for example a simple male or female terminal equipped with these connection means or these closure means, or a quick-release connection system element. 
     It will further be noted that the material of these first and second connectors of the invention to be heated may be adapted to facilitate heat transfer by conduction from the heating elements, consisting by way of nonlimiting example of a thermally conductive plastic. 
     These electrical connection means and circuit closure means are thus advantageously adapted to be heated by n pipes of the line (where n is an integer equal to or greater than 1) via: 
     electrical connections between, on the one hand, the pair of heating elements of the or each pipe and, on the other hand, the electrical connection means or the closure means, depending on the position of the pipe in the line, and 
     electrical cables which include the power supply means and are connected to the electrical connection means of the first connector to be heated at said first line end. 
     If n is equal to or greater than two (i.e. for at least two pipes), two consecutive pipes are connected together via the respective electrical connection means which equip two first adjacent intermediate connectors to be heated and are themselves electrically connected to each other by two coupled electrical connectors. 
     According to another feature of the invention, said electrical connection means may include two separated metal contacts that are respectively connected, on the one hand, to the two electrical cables and, on the other hand, to the two heating elements of said or each pair by said electrical connections and said circuit closure means may then include a single metal contact that is connected to the corresponding two heating elements. 
     Each of said contacts is preferably in the form of a cylindrical sector mounted around the corresponding connector to be heated and is locked in a circumferential groove on the latter, the two contacts of said electrical connection means being diametrically opposite each other. 
     The or each electrical connection with which each contact is provided to receive a heating element may advantageously be fastened to this contact and extend it axially toward the adjacent connector to be heated. 
     According to another feature of the invention, at least one of said contacts may further support a thermal protection component and/or another heating component, for example with a positive temperature coefficient, so as to provide protection against overheating, automatic regulation of the temperature in the line and/or to add heating power locally, respectively. 
     According to another feature of the invention, each of the first and second connectors to be heated provided with the corresponding contact or contacts may be covered by an electrically insulative bush defining the radially external envelope of the corresponding connector and is provided with an axial spigot for connecting it to the corresponding pipe. This bush may be fluid-tight and may be overmolded or otherwise attached, and in the latter case optionally adhesively bonded. 
     According to another, optional feature of the invention, a clip-on quick-release connection system may be mounted via this bush on at least one of these connectors to be heated to form a quick-release connection system, this quick-release connection system being optionally provided with a device for indicating correct connection of a male terminal into this quick-release connection system. 
     The or each pair of heating elements preferably includes two heating wires that are wound in a cylindrical helix and preferably intended to be mounted radially outside the corresponding pipe. 
     According to another aspect of the invention, said heating device further incorporates the or each pipe of said line to be heated, which pipe is preferably produced in a plastic material. 
     It is even more preferable if said or each pair of heating wires is wound in a cylindrical helix radially outside and in contact with the corresponding pipe, a thermally insulative sleeve surrounding the or each pipe provided with these wires. This bush then advantageously connects said clip-on quick-release connection system to this sleeve so as to fasten the corresponding pipe and the quick-release connection system. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Other features, advantages and details of the present invention will emerge on reading the following description of embodiments of the invention, said description being given by way of illustrative and nonlimiting example with reference to the appended drawings, in which: 
         FIG. 1  is a partial diagrammatic view in axial section of a heating device of one embodiment of the invention in relation with a pipe of the line to be heated, only the first connector to be heated defining a first end of the line being visible therein, 
         FIG. 2  is a perspective view of a heating device conforming to the principle of  FIG. 1 , in the case of a line with only one pipe (not shown), also showing the second connector to be heated at a second end of the line, 
         FIG. 3  is a diagrammatic plan view showing a heating device that is a variant of the  FIG. 2  device generalizing the invention to a line with two pipes connected in series, showing the insertion between the first and second line ends of two other first connectors for connecting these two pipes together and heated by the latter, and 
         FIG. 4  is a diagrammatic partial perspective view showing details of the device from  FIG. 3 , the two pipes that heat the two intermediate connectors and the two end connectors not being visible. 
     
    
    
     DETAILED DESCRIPTION 
     The heating device  1  from  FIGS. 1 and 2  is adapted to heat at the same time a single pipe  2  and first and second quick-release connection systems  3  and  4  including respective first and second connectors  5  and  6  to be heated between which this pipe  2  is mounted and which thus define the opposite first and second ends L 1  and L 2  of the fluid transfer line L. As previously indicated, it will be noted that these connectors  5  and  6  could be simple connection inserts, for example male terminals, instead of the quick-release connection systems  3  and  4 . 
     In the  FIG. 1  example, the first connector  5  to be heated is used in conjunction with a clip-on quick-release connection system  7  into which is locked a male terminal  8  provided with a peripheral locking projection  8   a  and with a device  9  for indicating correct connection of this male terminal  8  in the quick-release connection system  7 . This indicator device  9  may for example be that described in the patent EP-B1-1 770 321 or the patent application filed under the number FR0902113,both in the name of the Applicant. As can be seen in  FIG. 1 , in this example a first seal  10  is disposed radially between the connector  5  and this male terminal  8  and a second seal  11  is disposed radially between this connector  5  and the pipe  2 . 
     This first heated connector  5  (visible on the left in  FIG. 2 ) has a circumferential groove  5   a  to which are welded or crimped, for example, two metal heating contacts  5   1  and  5   2  each of cylindrical arc shape the edges of which espouse those of the groove and which are spaced on the circumference of the latter and diametrically opposite each other (these contacts  5   1  and  5   2  may be mounted other than by welding or crimping). These contacts  5   1  and  5   2  are respectively connected, on the one hand, to two electrical power supply cables  12   1  and  12   2  and, on the other hand, by electrical connections  13   1  and  13   2  to two heating wires  14   1  and  14   2  intended to be disposed along the pipe  2 . Moreover, this connector  5  is provided at its axial end facing toward the pipe  2  with a spigot  5   b  for connecting it to this pipe  2 , for example a spigot of barbed shape. 
     As for the second connector  6  to be heated (visible on the right in  FIG. 2 ), it incorporates circuit closure means formed of a single metal contact  6   12  of cylindrical arc shape which is for example welded or crimped to a groove  6   a  on the connector  6  like the two contacts  5   1  and  5   2  of the connector  5  and which closes the electrical circuit because it is itself connected to the two adjacent ends of the heating wires  14   1  and  14   2  by electrical connections  15   1  and  15   2 . Moreover, this connector  6  is provided at its axial end facing toward the pipe  2  with a terminal  6   b  for connecting it to this pipe  2  similar to the previous one. 
     The electrical connections  13   1 ,  13   2 ,  15   1 ,  15   2  between each contact  5   1 ,  5   2 ,  6   12  and the heating wire or wires  14   1  and  14   2  are in this example of the pin type axially extending the corresponding contact  5   1 ,  5   2 ,  6   12  toward the opposite connector  5 ,  6  to be heated. It should nevertheless be noted that these connections  13   1 ,  13   2 ,  15   1 ,  15   2  could be structured differently, provided that the heating wires  14   1  and  14   2  can be electrically powered by the current fed by the two cables  12   1  and  12   2  (which could of course be arranged in a different manner to that shown in  FIG. 2 , given that it is necessary and sufficient for these cables  12   1  and  12   2  to define + and − poles in relation to the two contacts  5   1  and  5   2  of the first connector  5 ). 
     As shown in  FIG. 1 , the two heating wires  14   1  and  14   2  are preferably wound in the form of a cylindrical helix on the radially external face of the pipe  2 , which may by way of nonlimiting example be produced in a thermoplastic material such as a polyamide (for example PA12). It will nevertheless be noted that it would be possible in the context of the present invention to provide this winding of heating wires  14   1  and  14   2  elsewhere than on the exterior of the pipe  2 , for example in the wall of the latter. 
     As also shown in  FIG. 1 , this connector  5  to be heated and the contacts  5   1  and  5   2  that it incorporates are covered by an electrically insulative bush  16  that defines the radially external envelope of the corresponding quick-release connection system  3  and which, in this example, fixes this connection system  3  to the pipe  2  by gripping a thermally insulative flexible sleeve  17  mounted around this pipe  2  so as to surround the heating wires  14   1  and  14   2  axially as far as the facing end of this bush  16 . 
     Thus it is clear that the electrical power supply to each of the two contacts  5   1  and  5   2  of the first connector  5 , which contacts  5   1  and  5   2  are electrically connected to the two wires  14   1  and  14   2 , respectively, extending along the pipe  2 , makes it possible: 
     to heat the pipe  2  because these electrically powered contacts  5   1  and  5   2  are respectively connected to the wires  14   1  and  14   2  and the single contact  6   12  equipping the second connector  6  closes the electrical circuit, and then to heat these contacts  5   1 ,  5   2 ,  6   12  and thus the connectors  5  and  6  incorporating them, and, optionally 
     to have these contacts  5   1 ,  5   2 ,  6   12  serve to support a thermal protection component (for example a positive temperature coefficient (PTC) component, not shown) and/or serve to support another heating component (also a PTC component, for example). 
     In the variant of the invention shown in  FIGS. 3 and 4 , the line L′ heated by the device  1 ′ of the invention comprises: 
     two pipes  2 ′ and  2 ″ of which one pipe  2 ′ is disposed between first and second parts  18  and  19  of an automobile vehicle and the other pipe is disposed between the second part  19  and a third part  20  of the vehicle (only the pairs of wires  14   1  and  14   2  for heating them can be seen in  FIG. 4 ), and 
     four connectors  5 ,  5 ′,  5 ″ and  6  to be heated that are for example included in quick-release connection systems of these pipes  2 ′ and  2 ″ and that comprise two first intermediate connectors  5 ′ and  5 ″ each connected to a pipe  2 ′,  2 ″. 
     To be more precise, this device  1 ′ includes: 
     two first connectors  5  and  5 ′ to be heated at the ends of the pipe  2 ′ (i.e. each with two separate contacts  5   1  and  5   2  respectively connected to the two wires  14   1  and  14   2  of this pipe  2 ′), of which one  5  forms the first line end L 1 ′ and is therefore electrically powered by the cables  12   1  and  12   2  and of which the other  5 ′ occupies an intermediate position in the line L′, each of these connectors  5 ,  5 ′ being similar to that described above with reference to  FIGS. 1 and 2 , 
     another first connector  5 ″ to be heated at an intermediate position in the line L′, mounted at the end of the other pipe  2 ″ adjacent to the connector  5 ′, and connected to the latter by male and female electrical connectors  21  and  22  plugged one into the other and respectively provided with cables  21   1 ,  21   2  and  22   1 ,  22   2  for connecting them to the contacts  5   1  and  5   2  of the connectors  5 ′ and  5 ″, and 
     a single second heated connector  6  at the other line end L 2 ′ (i.e. with a single contact  6   12  connected to the two adjacent wires  14   1  and  14   2  so as to close the electrical circuit powered by the cables  12   1  and  12   2 ) that is identical to that from  FIG. 2 , for example. 
     It will be noted that this device  1 ′ from  FIGS. 3 and 4  advantageously includes only one electrical power supply  12   1  and  12   2  for both the heating pipes  2 ′ and  2 ″. It is therefore clear that it is possible using the device  1 ′ of the invention to heat satisfactorily the whole of the line L′ (pipes and quick-release connection systems inclusive) with a single pair of electrical power supply cables  12   1  and  12   2 . 
     It will also be noted that this variant of  FIGS. 3 and 4  may be generalized in the same manner to more than two heating pipes, given that it is sufficient to add between two consecutive heating pipes a pair of electrical connectors  21 ,  22  respectively connected to the two contacts  5   1  and  5   2  of the corresponding first intermediate connectors.