LU100736B1

LU100736B1 - Blowby Heater

Info

Publication number: LU100736B1
Application number: LU100736A
Authority: LU
Inventors: Francis Graziotin
Original assignee: Cebi Luxembourg S A
Priority date: 2018-03-16
Filing date: 2018-03-16
Publication date: 2019-10-01

Abstract

A Blowby heater comprises: a conduit (12; 112) for a fluid to be heated; a plastic body (14; 114) with a passage defining an inner space in which the conduit is accommodated; the body (14; 114) comprises a heater container (18; 118) defining a cavity (20; 120) in which a heater stack (22; 122) is arranged; wherein the cavity has an aperture (24; 124) allowing insertion of, and access to, said heater stack, said aperture being sealably closed by a removable connector (26; 126); and wherein the heater stack is arranged in said cavity in thermal transfer with said conduit to heat-up the latter when energized by means of power provided through poles integrated in said connector. The heater stack comprises a heat transfer member (32; 132) arranged in an orifice (30; 130) of said heater container to be in direct contact with said conduit; and in that a seal ring (34; 134) is arranged at the interface between said heat transfer member and said orifice to sealably close the cavity.

Description

P-ELTH-006/LU 1 LU100736

Blowby Heater

FIELD OF THE INVENTION

The present invention generally relates to the field of crankcase breathing. Inparticular the invention relates to a heater system or "blowby heater" of acrankcase fluid.

BACKGROUND OF THE INVENTION "Blowby heaters" (also spelled “Blow-by”) are devices which can be used inrecent automobile vehicles with combustion engines in order to preventleakages. During operation of the combustion engine, "blowby" gazes can leakbetween the cylinders and the combustion chambers and accumulate as blowbyfluid in the crankcase of the combustion engine. This blowby fluid generallycontains a mixture of gas, oil, water and other combustion elements and itsaccumulation can generate leakage through the crankcase. Recent combustionengines are constructed to re-inject said blowby fluid into the combustionengine, for example via the air inlet into the engine. The blowby heater can beused to heat the fluid as it is circulating from the crankcase towards the air inletin order to improve the fluid flow, in particular in heavy winter conditions inwhich the blowby heater prevents the water contained in the fluid from freezing. A blowby heater well known in the art comprises a heater element such as aPositive Temperature Coefficient (PTC) element as a heating source. The PTCgenerates heat when crossed by an electrical current and it presents a variableresistance with its temperature for a heating power auto regulation.Misplacement of elements of the blowby heater in case of shock andcontamination from the environment can, separately or in combination, lead toshort circuit and eventually cause a fire. A conventional design of blowby heater system for a fluid comprises a heaterplate, e.g. a PTC plate, between two contact plates each equipped with anelectrical contact leg in order to transfer electrical current through the heaterplate. One of the contact plates rests on the wall of the conduit carrying the fluid

P-ELTH-006/LU 2 LU100736 for heat energy transfer. This assembly of heater plate and contact plates onthe conduit is overmolded with plastic to form a sleeve-shaped bodysurrounding the conduit. The heater assembly is thus covered with plastic, onlythe contact legs protrude through the body, ready for connection with aconnector. This conventional design is somewhat cumbersome in that itrequires pre-assembling the heater plate with the contact members on the tubebefore overmolding, running the risk of misplacement and hence of short-circuits or fire, as evoked above. WO 2018/015383 A1 discloses an alternative design of Blowby heater, whereinthe plastic body surrounding the conduit comprises a heater container having aclosed bottom forming a transfer wall in contact with the conduit, the heatercontainer further having an upper aperture that is closed by a connector. Theheater assembly is formed as a heater stack including an upper contact plate, aheater plate (PTC) and a lower contact plate resting against the transfer wall.The positioning of the heater plate is ensured by means of protrusionsextending from the transfer wall and engaging the peripheral edge of the heaterplate in order to maintain the heater plate on one contact zone of the conductiveplate at distance with one electrical connection zone of the conductive platesituated in front of said portion of the peripheral edge. Such blowby heater hasseveral benefits. The heater container forms a sealed cavity in which heaterstack is protected from dust and fluids. At assembly, the heater stack can be putin place in the cavity, ensuring proper positioning and avoiding the need forextra tests. The positioning protrusions ensure a proper positioning atinstallation and in use. A shortcoming of this otherwise well performing design isits somewhat slow response time (time required to reach a predeterminedtemperature of the conduit) due to the plastic transfer wall closing the cavity.

OBJECT OF THE INVENTION

The object of the present invention is to provide a solution which overcomes thedisadvantages of the prior art. In particular, the object of the invention is toprovide a heater system that is of simple and robust design, namely reducingrisks of short circuits, with a good response time.

P-ELTH-006/LU 3 LU100736

This object is achieved by a heater device as claimed in claim 1.

SUMMARY OF THE INVENTION

The present invention concerns a heater device, in particular for a crankcasefluid, comprising a conduit for the fluid to be heated; and a plastic body with apassage defining an inner space in which the conduit is accommodated. Thebody comprises a heater container defining a cavity in which a heater stack isarranged. In use, the cavity is sealably closed whereby the heater stack isprotected from dust and vapors. The cavity has an outer region with an apertureallowing insertion of, and access to, the heater stack. The aperture is closed,preferably in a sealed manner, by a removable connector. The heater stack isarranged in the inner region of the cavity in thermal transfer with the conduit toheat-up the latter when energized by means of power provided through polesintegrated in the connector.

According to the invention, the heater stack comprises a heat transfer memberarranged in an orifice of said heater container to be in direct contact with saidconduit (while closing said orifice). A seal ring is arranged at the interfacebetween the heat transfer member and the orifice to sealably close the cavity.

The present heater device presents the advantages of a closed and sealedheater container chamber as known e.g. from WO 2018/015383, however withan improved response time thanks to the heat transfer member sealablymounted in an orifice at the bottom of the plate. The heater stack is thereby indirect contact with the conduit, improving the heat-up response time (timerequired to heat the conduit up to a predetermined temperature). Firstexperiments have shown a reduction in response time in the order of 30 to 50%.The present design is further interesting in terms of energy savings, since thecurrent evolution follows the expected plateau evolution, avoiding peaks thatwere due to the difficulty of dissipating heat through a plastic end wall.

Furthermore, the use of a heater body with heater container permits propermounting of the heater stack therein, and provides protection against dust and

P-ELTH-006/LU 4 LU100736 fluids. This is of advantage in terms of simplicity and robustness of design,namely since it reduces risks of short circuits.

As will be understood, for improved heat transfer to the conduit the transfermember is advantageously made from a material having a better thermalconductivity than the plastic body. The transfer member may generally be madefrom metal, in particular from aluminum or aluminum alloy, copper or copperalloy, or brass. Metals/alloys having good thermal conductivity are preferred.

Also for improved heat transfer the conduit has a flattened wall portion and theheat transfer member is in contact therewith.

The term "heater stack" is used herein to refer to the piled-up assembly of theheater plate and heat transfer member, possibly with other plates such as e.g. acontact plate(s).

The heater plate is the heating source of the heater stack. The heater plate maybe any appropriate heating element providing heating by the Joule effect.Preferably, the heater plate is made from a Positive Temperature Coefficient(PTC) material.

In one embodiment, the cavity is closed at its bottom by an end wall in contactwith the conduit, the orifice for the heat transfer member being arranged in saidend wall. The heat transfer member may be a plate or disk like member with acircumferential groove in its peripheral edge in which the seal ring is arranged.The heater stack may here include the heat transfer member, a first contactplate, the heater plate, and optionally another contact plate, in this order. Thefirst contact plate may be provided with protruding features to maintain theheater plate in position and form an electric contact.

In a more specific embodiment, the first contact plate has a cross-section largerthan the orifice in the end wall. One or more principal protrusions, preferablycylindrical pins, extend from the transfer wall, through the first contact plate, andare arranged to engage a portion of the peripheral edge of the heater plate inorder to maintain the heater plate on a contact zone of the first contact plate atdistance from one electrical connection zone of said first contact plate situatedin front of the portion of the peripheral edge. Since the first contact plate,

P-ELTH-006/LU 5 LU100736 typically made from metal (Al or Cu or alloys thereof), is sandwiched betweenthe heater plate and heat transfer member, it will efficiently transfer heat to theheat transfer member. A first spring provides an electrical link between a first pole of the connector andthe heater stack, while pressing the latter towards the conduit. A second springis electrically linked with a second pole of the connector and presses againstthe electrical connection zone of the first contact plate.

In another embodiment, the heater stack includes a cup-shaped heat transfermember and the heater plate is located inside the cup-shape heat transfermember. The heat transfer member has a bottom wall in contact with theconduit and an outwardly bent upper edge. The seal ring is arranged around theheat transfer member below the upper edge. Preferably, the orifice issurrounded by an annular sealing surface configured for receiving the seal ringwhen the heat transfer member is mounted therein, the seal ring beingcompressed between the sealing surface and the upper edge, in order to causeradial expansion of the seal ring against an annular wall surrounding the sealingsurface.

In this embodiment, a first spring provides an electrical link between a first poleof the connector and the heater stack, while pressing the latter towards theconduit. A second spring is electrically linked with a second pole of theconnector and presses against the outwardly bent upper edge cup-shaped heattransfer member without touching the heater plate.

The body is a plastic part that can be independently manufactured by molding.Any appropriate material for the plastic body may be used, e.g. PA (in particularPA66, PPA, or PBT, with or without hydrolysis treatment and preferably withglass fiber (about 30%). Alternatively the body may be overmolded on saidconduit. In both cases, of course, the body is provided with the heater containerthat is integral therewith. Also the orifice at the bottom of the heater cavity isprovided at the time of molding/overmolding.

According to another aspect, the invention also concerns a method ofmanufacturing a heater device as claimed in claim 14.

P-ELTH-OO6/LU 6 LU100736

BRIEF DESCRIPTION OF THE DRAWINGS

Further details and advantages of the present invention will be apparent fromthe following detailed description of not limiting embodiments with reference tothe attached drawing, wherein:

Figure 1: is a perspective view of a first embodiment of the present heaterdevice;

Figure 2: is an exploded view of the heater device of Fig.1 ;

Figure 3: is a cross-sectional view of the heater device of Fig. 1 ;

Figure 4: is an exploded view of a second embodiment of heater device; and

Figure 5: is a cross-sectional view of the heater device according to the secondembodiment.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS A first embodiment of the present heater device 10 is shown in Figs. 1 to 3. Theheater device 10 has been particularly designed for heating up blowby fluid ofinternal combustion engines and is therefore referred to as “blowby heater” inthe rest of the description. Blowby heater 10 comprises a conduit 12 for theblowby fluid to be heated, and a plastic body 14 with an inner passage in whichthe conduit 12 is accommodated. The body 14 preferably completely surroundsthe conduit, forming a kind of outer sheeting or envelope.

Such blowby heater 10 is generally inserted in a blowby fluid return line, inwhich it is connected by its opposite connection portions 17. The skilled personwill understand that conduit 12 may have various dimensions, shapes andcross-sections.

The body 14 as shown in Fig. 2 comprises a heater container 18 at theperiphery of the conduit that extends transversally/radially. The heater container18 defines a cavity 20 in which a heater stack 22 is arranged.

P-ELTH-006/LU 7 LU100736

The cavity 20 has an aperture 24 by which it is open transversally (outwardlywith respect to the internal passage). A connector 26 is attached, preferablyremovably, to the body 14 and is adapted to close the aperture 24 of the heatercontainer 18 in order to close and preferably seal the cavity against dust andfluids/vapors. Connector 26 may be attached to the heater container by anysuitable releasable connection means 27, like for example a ratchetmechanism, or a snap locking mechanism as shown in Fig. 1. Additionally oralternatively, the connector is ultrasonically welded to the body, providing anefficient sealing of the cavity. However a seal ring could be used. The connector26 and/or the body 14 may be made from any appropriate plastic material, e.g.PBT or PA.

It may be noted that such a plastic body with integrated heater container hasthe advantage of allowing mounting of the heater stack when the plastic body isalready on the conduit. The heater stack can be inserted and mounted in thecavity via aperture 24, which also permits further access to the heater stackwhere necessary. As it will be understood, such plastic body with heatercontainer can be manufactured as a molded part that is fitted over the conduit12 (and maintained by way of press-fit, shape-fit, etc.) or may be overmolded onthe conduit 12.

The heater stack 22 is arranged in the cavity 20. It is selectively energized bymeans of power provided through poles 28 integrated in the connector 26. Theheater stack 22 transforms the electric energy provided through the connectorinto heat that is transferred to the conduit 12 in order to heat it up.

As will be described in more detail below, the heater stack 22 comprises at leasta heater plate 38, forming the heat source of the blowby heater 10, and a heattransfer plate 32. Depending on the embodiments, the heater stack maycomprise other intervening plates. The heater container 18 comprises an orifice30 disposed in an end wall 31 closing the bottom of the container 18 at theinterface between the cavity 20 and the conduit 12. In that manner the orifice 30provides passageway from the cavity 20 to the conduit 12. As it will be

P-ELTH-006/LU 8 LU100736 understood, the size of the orifice in the end wall 31 may vary depending on theembodiments.

The heat transfer plate 32 of the heater stack 22 is arranged in the orifice 30 ofthe heater container 18. The heat transfer plate 32 is in direct contact with theconduit 12 and closes the orifice 30. The heat transfer plate 32 is made from amaterial having a better thermal conductivity than the plastic body. For example,the transfer plate may be made from a metal, in particular from aluminum oraluminum alloy, copper or copper alloy, or brass. The material of the transferplate may typically be matched with that of the conduit.

When the heater stack 22 is energized to generate heat, the transfer plate 32receives this energy which is transferred by direct contact to the conduit 12.Such design with a sealingly mounted transfer plate gives the advantages of asealed heater cavity similar to WO 2018/015383, however with improvedresponse time since heat is transferred through the heat transfer member andnot though a plastic wall. Heat-up time can be reduced by up to 50%.

For an improved contact, the conduit 12 advantageously comprises a flattenedwall portion 33 and the heat transfer plate 32 lies against this flattened wallportion 33. A seal ring 34 is arranged at the interface between the heat transfer plate 32and the orifice 30 to close the cavity. The seal ring 34 seals the cavity andprevents dust and vapor to enter the cavity from the orifice 30. The seal ring 34is preferably a plastic ring made for example of FKM of AEM, or any suitablematerial.

In this embodiment, the transfer plate 32 has a thickened disk shape andcomprises a circumferential groove 35 in its peripheral edge, in which the sealring 34 is arranged.

In the embodiment of Figs. 2 and 3, the heater stack 22 comprises a contactplate 36, a heater plate 38, a first contact plate 40, and the heat transfer plate32 at the bottom.

P-ELTH-006/LU 9 LU100736

As the heat source, the heater plate 38 is a heating element that transformselectric energy into heat by the Joule effect. Conventionally, the heater plate 38may be made from PTC conductive material. The heater plate is here shapedas a disk, but other shapes can be used.

When traversed by electrical current, the heater plate 38 will generate heat thatis taken up by the first contact plate 40 and radiated therefrom to the heattransfer plate 32 to be finally transferred to the conduit 12.

During assembly of the heater stack 22 in the cavity 20, the heat transfer plate32 and the seal ring 34 are first installed in the orifice 30 of the container 18closing the orifice 30, such that the transfer plate 32 is in direct contact with theconduit. The other elements of the heater stack 22 may then be piled up on topof the transfer plate 32.

Electrical connection of the heater stack is achieved by means of a firsthélicoïdal contact spring 42 on top of the contact plate 36 and a secondhélicoïdal contact spring 44 on top of the first contact plate 40.

The contact springs 42, 44 are configured to press the elements of the heaterstack 18 together, and thus maintain a physical contact between them. Asshown in Fig. 3, when the connector 26 closes the heater container 18, thecontact springs 42, 44 are compressed between the connector 36 andrespectively the contact plate 36 and the first contact plate 40.

First contact plate 40 is advantageously designed to ensure a simple andreliable mounting of the heater plate, providing safe positioning and electricalconnections. The first contact plate 40 is typically made from a metal havinggood electric conductivity (Al or Cu or alloys thereof), and hence generallyexhibiting good thermal conductivity. As shown in Fig. 2, the first contact plate40 comprises two principal openings 46, two secondary openings 50 oppositethe secondary openings, and finally one auxiliary opening 48. It may be noticedthat the auxiliary opening 48 has a larger diameter than the other openings.

Turning to Fig.3, two principal protrusions 52, here two cylindrical pins, extendfrom the end wall 31 (through principal openings 46) and are arranged toengage a portion of a peripheral edge of the heater plate 38 in assembled

P-ELTH-006/LU 10 LU100736 position, in order to maintain the heater plate 38 on a contact zone of the firstcontact plate 40 at distance from an electrical connection zone on the firstcontact plate 40 situated in front of the portion of the peripheral edge.

The end wall 31 may further comprise two secondary protrusions 56 adapted tocooperate with the two secondary openings 50, and one auxiliary protrusion 54adapted to cooperate with the auxiliary opening 48.

Fig. 3 shows only one principal protrusion 52 and one secondary protrusion 56,the other protrusions are disposed symmetrically relative to the plane of thecross-section of Fig. 3.

In order to position the first contact plate 40, the plate 40 is arranged in theheater container 18 such that the principal, auxiliary and secondary protrusions46, 48, 50, from the end wall 31, are respectively extending through theprincipal, auxiliary and secondary openings 52, 54, 56 of the first contact plate40. Once in place, the first contact plate 40 covers the heat transfer plate 32and at least part of the end wall 31.

After positioning the first contact plate 40, the heater plate 38 is disposed on topof the latter in between the primary and secondary protrusions 52, 56. It shouldbe noted that the dimensions of the heater plate 38 are predetermined in orderto fit between the protrusions, preferably in contact with the protrusions.

The contact plate 36 is then disposed on top of the heater plate 38. In order toease the positioning, the dimensions of the contact plate are roughly the sameas the dimensions of the heater plate.

The contact plate 36 further comprises a nipple 58 that extends from the centerof the contact plate 24. The first contact spring 42 is disposed on top of thecontact plate 36 and cooperates with the nipple 58.

The first and second contact springs 42, 44 are positioned in the cavity asfollows. The second spring 42 engages with the auxiliary protrusion 40 providedin the wall 31 that passes through the first contact plate 40. In the presentembodiment, the auxiliary opening 48 in the first contact plate 40 comprises a

P-ELTH-006/LU 11 LU100736 raised edge 60 forming an electrical connection zone and the second spring 44engages with the auxiliary protrusion 54 resting on the raised edge 60.

The first and second springs 42 and 44 are connected to corresponding strips62 in the connector for power supply. The electrical power is supplied to thesprings via a pair of wires (not shown) arriving at the connector 14. Heating willoccur when a voltage is applied to the heater contact strips via the wires.

In the final assembly stage, the connector 26 is mounted on the aperture toclose the cavity 20 of the heater container 18.

When the connector 26 is fixed on the heater container, the first spring 42 iselectrically linked with the first connector pole and presses the elements of theheater stack 22 toward the conduit 12. The second spring 44 is electricallylinked with the second connector pole and presses against the electricalconnection zone the first contact plate 40. A second embodiment of blowby heater 100 will now be described withreference to Figs. 4 and 5. This embodiment essentially differs from theprevious one by the design of the heater stack. Same or alike elements willtherefore be designated by same reference signs, augmented by 100.

In Fig.4 one will recognize the blowby heater 110 with the conduit 112accommodated in the inner passage of plastic body 114.

The body 114 comprises a heater container 118 defining a cavity for a heaterstack 122.

The heater stack 122 here comprises a cup-shaped heat transfer member 132and a heater plate 138. If desirable, a contact plate may be installed on top ofthe heater plate.

The heat transfer plate 132 is here shaped as a circular cup comprising abottom wall 166 surrounded by a peripheral wall 167 ending with an outwardlybent upper edge 168.

As shown in Fig. 5, the heat transfer member 132 is mounted in an orifice 130of the heater container 118 such that its bottom wall 166 is in contact withconduit 112.

P-ELTH-OO6/LU 12 LU100736

The orifice 130 here extends over most of the cross-section of the heatercontainer. Orifice 130 is defined by an inner bottom border 131, lying on conduit112. More precisely the orifice 130 is surrounded by an annular sealing surface170 internally located on said bottom border 131 and configured for receiving acorresponding seal ring 134 when the heat transfer member 132 is mountedtherein. The internal bottom border is actually partially curve-shaped so that thesealing surface 170 is further outwardly limited by a raised annular wall 172surrounding the latter.

The elastic seal ring 134 is typically positioned on the outer periphery of thecup-shaped transfer member 132, below the outwardly bend edge 168. Uponassembly of the transfer member 132, the seal ring 134 will be compressed bythe edge 168 against the sealing surface 170, causing radial expansion of theseal ring further compressed against annular wall 172 and the wall 167 of thetransfer member. This design provides a quality sealing of cavity bottom againstvapors/fluids.

On the side of the bottom wall 166 that is not in contact with the conduit 112,the heater plate 138 comprises an annular slanted surface 174 surrounding thebottom wall 166.

The heater plate 138 is received inside the cup-shaped transfer member 132,resting on top the bottom wall 166 shown in Fig. 5. The heater plate 138 islocated inside the cup-shaped heat transfer plate 132. An annular slantedsurface 174 is inside member 134 at the transition between wall 167 and bottom166 to act as a centering means for the heater plate 138. A pair of contact springs 142 and 144 is used to provide electric links betweenthe connector 126 and heater stack 122. These are maintained in spacedrelationship by a guide element 164 on top of the heater stack 122.

The guide element 164 comprises a positioning plate 174. The dimensions ofthe positioning plate 174 preferably match the internal cross-section of theheater cavity. The guide element 164 further comprises two guiding cylinders176, 176’ defining two holes on the surface of the positioning plate 174. The

P-ELTH-006/LU 13 LU100736 dimensions of the guiding cylinders 176, 176’ are adapted to the dimensions ofthe first and second spring 142, 144.

Once the guide element 164 is in place, the first and second springs 142, 144are inserted into the guiding cylinders 176. One guide cylinder 176 positions the 5 first spring 142 such that it presses the heater stack 122 from the top of the heater plate 138 towards the conduit 112. The other guide cylinder 176’positions the second spring 144 such that it presses against the outwardly bentupper edge 168 of the cup-shaped heat transfer member 132, however withouttouching the heater plate 138. It may be noticed that guide element 16410 comprises below plate 174 a disk shaped locating portion 175 having a diameter corresponding to the inner diameter of the cup member 132. Thelocating portion 175 rests against heater plate 138 and has a heightcorresponding to the difference between the cup depth and the heater platethickness. Locating portion 175 is traversed by spring 142, but not by spring15 144, thus avoiding short-cuts with the heater plate. Here again the connector 126 sealingly closes the cavity 120 and exerts the compressive force on thesprings 142 and 144.

Claims

1. Dispositif de chauffage (10 ; 100), en particulier pour un fluide de carter,comprenant : une conduite (12 ; 112) pour un fluide devant être chauffé ; un corps plastique (14 ; 114) avec un passage définissant un espaceintérieur dans lequel la conduite est reçue, ledit corps (14; 114)comprenant un réceptacle (18 ; 118) de chauffe définissant une cavité(20 ; 120) dans laquelle un empilement chauffant (22 ; 122) est agencé ;dans lequel la cavité a une ouverture (24; 124) permettant l’insertiondudit empilement chauffant, ladite ouverture étant fermée par unconnecteur amovible (26 ; 126) ; et dans lequel l'empilement chauffant est agencé dans ladite cavité entransfert thermique avec ladite conduite pour chauffer cette dernièrelorsqu’il est mis sous tension au moyen d’une énergie électrique fourniepar l’intermédiaire de pôles intégrés dans ledit connecteur ; caractérisé en ce que ledit empilement chauffant comprend un élément(32 ; 132) de transfert de chaleur agencé dans un orifice (30 ; 130) duditréceptacle de chauffe pour être en contact direct avec ladite conduite ; eten ce qu’une bague d’étanchéité (34; 134) est agencée à l’interfaceentre ledit élément de transfert de chaleur et ledit orifice pour fermer demanière étanche la cavité.A heater (10; 100), particularly for a crankcase fluid, comprising: a conduit (12; 112) for a fluid to be heated; a plastic body (14; 114) with a passage defining an interior space in which the pipe is received, said body (14; 114) including a heater receptacle (18; 118) defining a cavity (20; 120) in which a stack heater (22; 122) is arranged; wherein the cavity has an opening (24; 124) for inserting the heating stack, said opening being closed by a detachable connector (26; 126); and wherein the heating stack is arranged in said thermal entransfer cavity with said conduit for heating the same when energized by electrical power supplied through poles integrated in said connector; characterized in that said heating stack comprises a heat transfer element (32; 132) arranged in an orifice (30; 130) of said heater receptacle to be in direct contact with said conduit; andin that a sealing ring (34; 134) is arranged at the interface between said heat transfer member and said orifice for sealing the cavity.

2. Dispositif de chauffage selon la revendication 1, dans lequel l’élément detransfert de chaleur est constitué d’un matériau ayant une conductivitéthermique meilleure que le corps plastique.The heating device according to claim 1, wherein the heat transfer member is made of a material having a better thermal conductivity than the plastic body.

3. Dispositif de chauffage selon la revendication 2, dans lequel l’élément detransfert de chaleur est constitué de métal, en particulier d’aluminium oud’un alliage d’aluminium, de cuivre ou d’un alliage de cuivre, ou de laiton.3. Heating device according to claim 2, wherein the heat transfer element is made of metal, in particular aluminum or an alloy of aluminum, copper or a copper alloy, or brass.

4. Dispositif de chauffage selon la revendication 1, 2 ou 3, dans lequel leditélément de transfert de chaleur est en contact avec une partie de paroiaplatie de ladite conduite.Heating device according to claim 1, 2 or 3, wherein the heat transfer element is in contact with a portion of the ply of said pipe.

5. Dispositif de chauffage selon l’une quelconque des revendicationsprécédentes, dans lequel ledit empilement chauffant inclut une plaque(38 ; 138) de chauffe, en particulier une plaque de chauffe CTP.Heating device according to any one of the preceding claims, wherein said heating stack includes a heating plate (38; 138), in particular a PTC heating plate.

6. Dispositif de chauffage selon l’une quelconque des revendicationsprécédentes, dans lequel la cavité est fermée en son fond par une paroi d’extrémité(31) en contact avec la conduite, ledit orifice étant agencé dans laditeparoi d’extrémité ; et l’élément (32) de transfert de chaleur est un élément de type plaque avecune rainure circonférentielle (35) dans son bord périphérique danslaquelle ladite bague d’étanchéité (34) est agencée.6. Heating device according to any one of the preceding claims, wherein the cavity is closed at its bottom by an end wall (31) in contact with the pipe, said orifice being arranged in said end wall; and the heat transfer member (32) is a plate-like member with a circumferential groove (35) in its peripheral edge in which said sealing ring (34) is arranged.

7. Dispositif de chauffage selon la revendication 6, dans lequel leditempilement chauffant (22) inclut ledit élément (32) de transfert dechaleur, une première plaque de contact (40), ladite plaque (38) dechauffe, et facultativement une autre plaque de contact (36).The heater of claim 6, wherein said heating stack (22) includes said heat transfer member (32), a first contact plate (40), said plate (38) heats, and optionally another contact plate (36).

8. Dispositif de chauffage selon la revendication 7, dans lequel laditepremière plaque de contact (40) a une section transversale plus grandeque ledit orifice dans ladite paroi d’extrémité ; et dans lequel une ouplusieurs saillies principales, préférablement des ergots cylindriques,s’étendent depuis la paroi de transfert, à travers ladite première plaquede contact, et sont agencées de manière à engager une partie du bordpériphérique de la plaque de chauffe afin de maintenir ladite plaque dechauffe sur une zone de contact de la première plaque de contact à unedistance d’une zone de connexion électrique de ladite première plaquede contact située en avant de ladite partie du bord périphérique.The heater of claim 7, wherein said first contact plate (40) has a larger cross-sectional area than said orifice in said end wall; and in which one or more main projections, preferably cylindrical lugs, extend from the transfer wall, through said first contact plate, and are arranged to engage a portion of the peripheral edge of the heating plate to maintain said plate warming on a contact area of the first contact plate at a distance from an electrical connection area of said first contact plate located in front of said peripheral edge portion.

9. Dispositif de chauffage selon la revendication 8, dans lequel un premierressort (42) fournit une liaison électrique entre un premier pôle duditconnecteur et ledit empilement chauffant (22), tout en pressant cedernier vers ladite conduite ; et un deuxième ressort (44) estélectriquement lié avec un deuxième pôle dudit connecteur et pressecontre la zone de connexion électrique (60) de ladite première plaque decontact (40).A heater as claimed in claim 8, wherein a first port (42) provides an electrical connection between a first pole of said connector and said heating stack (22) while pressing the latter toward said conduit; and a second spring (44) is electrically bonded to a second pole of said connector and presses against the electrical connection area (60) of said first contact plate (40).

10. Dispositif de chauffage selon l’une quelconque des revendications 1 à 5,dans lequel ledit empilement chauffant (122) inclut un élément (132) de transfert dechaleur en forme de coupelle et ladite plaque (138) de chauffe est situéeà l’intérieur dudit élément de transfert de chaleur en forme de coupelle ;ledit élément de transfert de chaleur en forme de coupelle a une paroi defond (166) en contact avec ladite conduite et un bord supérieur (168)replié vers l’extérieur ; et ladite bague d’étanchéité (134) est agencée autour dudit élément detransfert de chaleur en forme de coupelle en-dessous dudit bordsupérieur.The heater according to any of claims 1 to 5, wherein said heating stack (122) includes a cup-shaped heat transfer member (132) and said heater plate (138) is located therein said cup-shaped heat transfer member; said cup-shaped heat transfer member has a bottom wall (166) in contact with said pipe and an upper edge (168) folded outwardly; and said sealing ring (134) is arranged around said cup-shaped heat transfer member below said upper edge.

11. Dispositif de chauffage selon la revendication 10, dans lequel ledit orifice(130) est entouré par une surface d’étanchéité annulaire (170) configuréepour recevoir ladite bague d’étanchéité (134) lorsque ledit élément (132)de transfert de chaleur en forme de coupelle est monté dans celui-ci,ladite bague d’étanchéité étant compressée entre ladite surfaced’étanchéité (170) et ledit bord supérieur (168), afin de causer uneexpansion radiale de ladite bague d’étanchéité contre une paroiannulaire (172) entourant ladite surface d’étanchéité.The heater of claim 10, wherein said port (130) is surrounded by an annular sealing surface (170) configured to receive said seal ring (134) when said heat transfer member (132) cup shape is mounted therein, said sealing ring being compressed between said sealing surface (170) and said upper edge (168), in order to cause radial expansion of said sealing ring against a paranian (172) surrounding said sealing surface.

12. Dispositif de chauffage selon la revendication 10 ou 11, dans lequel unpremier ressort (142) fournit une liaison électrique entre un premier pôledudit connecteur et ledit empilement chauffant, tout en pressant ce dernier vers ladite conduite; et un deuxième ressort (144) estélectriquement lié avec un deuxième pôle dudit connecteur et pressecontre ledit bord supérieur (168) replié vers l’extérieur dudit élément detransfert de chaleur en forme de coupelle sans toucher ladite plaque dechauffe.A heater as claimed in claim 10 or 11, wherein: a first spring (142) provides an electrical connection between a first connector pole and said heater stack, while pressing the heater stack toward said conduit; and a second spring (144) is electrically bonded to a second pole of said connector and presses said upper edge (168) folded outwardly of said cup-shaped heat transfer member without touching said heat plate.

13. Dispositif de chauffage selon l’une quelconque des revendicationsprécédentes, dans lequel le corps (14; 114) est une pièce mouléeajustée par-dessus ladite conduite ou ledit corps est surmoulé sur laditeconduite.A heater as claimed in any one of the preceding claims, wherein the body (14; 114) is a molded piece over said pipe or said body is molded onto said pipe.

14. Procédé de fabrication d’un dispositif de chauffage comprenant : la fourniture d’une conduite reçue dans un corps plastique, ledit corpscomprenant un réceptacle de chauffe définissant une cavité pour unempilement chauffant, ladite cavité ayant une ouverture et un orificeouvrant sur ladite conduite ; l’agencement d’un empilement chauffant dans ledit réceptacle de chauffeà travers ladite ouverture, dans lequel ledit empilement chauffant inclutun élément de transfert de chaleur positionné dans ledit orifice en contactdirect avec ladite conduite, et dans lequel une bague d’étanchéité estagencée à l’interface entre ledit élément de transfert de chaleur et leditorifice pour fermer de manière étanche la cavité ; et la fermeture de ladite cavité au moyen d’un connecteur monté sur laditeouverture, ledit connecteur comprenant des pôles pour amener uneénergie électrique afin de mettre sous tension ledit empilement chauffant.A method of manufacturing a heater comprising: providing a conduit received in a plastic body, said body having a heater receptacle defining a cavity for a heating stack, said cavity having an opening and an opening opening on said conduit; arranging a heating stack in said heater receptacle through said opening, wherein said heating stack includes a heat transfer element positioned in said orifice in direct contact with said conduit, and wherein a seal ring is provided at the interface between said heat transfer element and the edifice for sealing the cavity; and closing said cavity by means of a connector mounted on said opening, said connector comprising poles for supplying electrical power to energize said heating stack.