FR2749921A1 - METHOD AND DEVICE FOR VIBRATION OF A DUCT IN A THERMAL ENCLOSURE - Google Patents

Abstract

The present invention relates to a method and an apparatus for the heat treatment of fluid, gaseous or liquid materials or products flowing in a conduit. In a method of vibrating a duct (4) in order to reduce or prevent a deposit of solid particles on the internal wall of said duct in which one or more fluids flow, which duct is at least partly disposed in an enclosure thermal (1), a transverse vibration produced by a mechanical vibrator (20) which is placed outside the thermal enclosure is applied to the duct, and said vibration is transmitted by means of an appendage (14, 60 ) forming part of a mechanical means for supporting or guiding said duct or else of a measuring instrument fixed to said duct. The technical sector of the invention relates to heat treatments in general, those implementing both heating and cooling and including a chemical reaction or not.

Description

Method and device for vibrating a conduit

in a thermal enclosure.

  The subject of the present invention is a method and apparatus for heat treatment of fluent or gaseous materials or products.

  liquid, flowing in a conduit.

  The technical sector of the invention relates to heat treatments in general, those using both a heating

  cooling and including a chemical reaction or not.

  Fluid materials or products subjected to heat treatments are likely to form deposits on the inner wall of a conduit in which they flow during their treatment. This can occur for example when steam cracking hydrocarbons to make olefins, or when cracking 1,2-dichloroethane to make vinyl chloride, or in heat exchangers.

  heat, for example chillers.

  It is known from the international application N WO 92/11931 (NAPHTACHIMIE SA) a process for manufacturing chemicals in which one or more reagents are circulated inside a tube arranged in a radiation zone of a furnace and wherein at least a portion of the tube is vibrated to limit reaction by-product deposits such as coke on the inner wall of the tube. This patent application proposes to cause a transverse vibration of the tube at a frequency of between 50 and 2000 Hertz, by a mechanical vibration generator disposed inside or outside the radiation zone of the furnace and connected to a tube via a mechanical connection. This document also describes an oven, such as a steam-cracking furnace, comprising a thermal radiation chamber, provided with burners, inside which is disposed a serpentine cracking tube consisting of a succession of sections. straight joined together by elbows; the oven is provided with an excitation means capable of generating a vibration of at least a portion of the tube which may be constituted by a vibration generator

  mechanical, connected to the tube by a mechanical connection.

  The object of the present invention is to propose a method and a device for vibrating a duct placed in a thermal enclosure (such as a radiation chamber of an oven) and in which

  one or more fluids flow, which are improved.

  The present invention more particularly aims to provide a method and an apparatus for vibrating a conduit which is disposed in a thermal chamber and in which flows a fluid, process and apparatus that are compatible with high thermal stresses. very high temperatures in the thermal enclosure (up to 1000 o C or 1500 o C), which are both simple, reliable, safety-compliant and long-lasting. life, that is to say capable of being implemented industrially at a reduced cost while having a robustness, reliability and safety sufficient, given the continuous nature of heat treatment operations and risks

  explosion in case of mechanical rupture of the duct.

  The solution to the problem posed consists in proposing a method for vibrating a duct to reduce or prevent deposition of solid particles on the inner wall of said duct in which one or more fluids flow, which duct is disposed in part to least in a thermal enclosure (for the heat treatment of said fluid or fluids), in which process is applied to the conduit a transverse vibration (or bending) produced by a mechanical vibrator which is disposed outside the thermal enclosure, in which said vibration (from said vibrator to said duct) is transmitted via an appendix (or prominent accessory of said duct) forming part of a mechanical means for supporting or guiding said duct or a measuring instrument (in particular measurement of

  pressure or temperature of said fluid or fluids) attached to said conduit.

  According to preferred embodiments: said appendage consists essentially of one or more metal parts fixed rigidly and immovably to one or more walls of said duct, preferably welded to a wall of said duct or constituting a single piece (for example by molding) with a part of the walls of said duct, which appendix is preferably of elongated shape, for example essentially consisting of a tube section (hollow) or rod (solid); said vibrator is (mechanically) connected directly to said appendix, or said vibrator is (mechanically) indirectly connected to one or more appendices via a connector (essentially consisting of a rigid metal structure) capable of transmitting said vibration; - The vibrations are applied by exerting a force in a direction substantially transverse or radial with reference to the longitudinal axis of a rectilinear section (tube) of said duct; said vibrator is removably attached to said connector or said appendix, for example by at least one screw or bolt; an electromagnetic vibrator powered by a source of variable frequency electrical energy is used; vibrations are applied to said duct at a frequency of less than 1000 hertz, preferably between 10 and 100 hertz

(especially between 20 and 60 Hertz).

  The vibrator exerts on the appendage, directly or through a connector, a force (or force) variable in time, preferably periodic and reciprocating, to cause a movement (or displacement) of the appendix, if necessary the connector (that is to say of the structure of transmission of the vibrations), and the duct, variable in the time and of average value null; this transverse vibration of the duct causes transverse deformation or bending of the elongate portions, for example tubular

rectilinear duct.

  The invention also provides an apparatus for applying transverse (or bending) vibrations produced by a mechanical vibrator to a conduit of which at least a portion extends within a thermal enclosure, which apparatus includes a means of attachment. mechanical rigid vibrator to a prominent appendix of the duct, which appendix is part of a mechanical means for supporting or guiding said duct or a measuring instrument (of

  pressure or temperature of said fluid or fluids) attached to said conduit.

  According to preferred embodiments of the apparatus according to the invention: - said vibrator is (mechanically) indirectly connected to one or more appendices (s) via a connector (essentially consisting of a rigid metal structure) able to transmit said vibration; the apparatus according to the invention comprises several vibrators respectively fixed or connected to one or more appendix (s) of said duct; said vibrator is an electromagnetic vibrator powered by a source of variable frequency electrical energy, preferably powered by a frequency and voltage variator, and is preferably capable of applying vibrations to said duct at a frequency of less than 1000 hertz, preferably between 10 and 100 hertz; said mechanical vibrator is fixed to said connector or said appendix by orientation means which allow an orientation of the axis of application of the vibration and / or of the alternating force generated by the mechanical vibrator; said vibrator is suspended from said connector or said appendix, and preferably the mass of said vibrator is less than or equal to 20 kilos, and preferably the vibrator is disposed at a small distance from an orifice provided in a wall of

  the thermal enclosure and through which extends said appendix.

  The solution to the problem posed also consists in proposing a device or apparatus for heat treatment of one or more fluids which comprises: a thermal enclosure, a conduit in which said fluid or fluids flow, which extends in part to less within said enclosure, and which comprises a prominent appendage of the conduit, which appendix is part of a mechanical means for supporting or guiding said conduit or a measuring instrument (in particular for measuring pressure or temperature of said fluid or fluids) fixed to said duct, a mechanical vibrator disposed outside the thermal chamber, and a mechanical connection means connecting said appendix

audit vibrator.

  According to preferred embodiments of the device according to the invention: - said appendix is fixed or incorporated in a bend (preferably at or 180 degrees) forming part of said conduit, - said appendix is elongate and extends substantially parallel to the longitudinal axis of a rectilinear section of tube forming part of said conduit, - said appendix consists essentially of a rod or a tube extending through an orifice provided in a wall forming part of the means delimiting the thermal enclosure, which appendix is attached or integrated to a bend disposed at one end of a straight pipe section of said conduit, and wherein said straight pipe section and said appendage extend substantially horizontally or vertically, - the largest dimension (or length) of said appendix is less than or equal to two meters, for example close to 0.1 meter to 1.0 meter, - the largest dimension (or length) of said is less than or equal to two meters, for example close to 0.1

1.0 meters.

  In general, the invention is applicable to processes and devices in which fluids are capable of causing solid deposition under the effect of heating, cooling or cooling.

chemical reaction.

  Surprisingly, it has been found that it is possible to apply (and transmit) the vibration to the duct by an appendage fitted to the duct, whereas according to a generally widespread prejudice, it is recommended to avoid vibrating such conduits; it is particularly advantageous to use an appendage serving as a means of measuring or controlling the temperature or pressure of the fluid or fluids flowing in the conduit, or part of a means

  mechanical support or guide said conduit.

  The appendix used may be disposed at any point of the duct or of a rectilinear section of tube or of a bend, preferably in the vicinity of one end of a rectilinear section of tube, or more

  particularly on a bend or a curvilinear section of tube.

  The mechanical vibrator may be directly or indirectly connected to at least one of the mechanical means for measuring or controlling the temperature or pressure of the fluid or fluids flowing in the conduit. One of these means may comprise a sheath or a rigid metal sheath that enters the conduit so as to measure or control the temperature or pressure of the fluid or fluids in the conduit. This can be a "thermowell" or a "thermowell" in which there is a thermocouple, or a rigid pipe for the measurement of a pressure or a pressure drop. Thus, in this case, the sheath, or the sheath, or the pipe is used to transmit the vibrations emitted by the vibrator to the pipe itself. In some cases, the mechanical means can be reinforced at its point of attachment with the conduit by making the mechanical means more rigid thanks to a metal part added and fixed or welded to

  all the mechanical means and the conduit.

  Thus, in the present invention, at least one of the mechanical appendages combines both the function of measuring instrument or control of the temperature or pressure of the fluid in the conduit or the support function or guide of the driven, with the function of vibration transmitter between the mechanical vibrator and the duct. The mechanical vibrator can be directly connected to at least one of these mechanical means (or appendices), in particular when these appendices comprise at least one external part disposed outside the thermal enclosure, for example when they open inside the enclosure and emerge outside the enclosure through a hole in a wall of the enclosure. The mechanical vibrator can also be indirectly connected to at least one of these appendages through a rigid mechanical connector. The connector makes it possible to connect the mechanical vibrator to at least one of these appendages, in particular to the external part of one of these appendages which is arranged outside the enclosure. In this case, the connector may be of extremely short length, for example from 20 to 200 millimeters. It can be relatively long, for example from 200 to 2,000 millimeters, especially when one of the appendages does not have an external part disposed outside the thermal enclosure, but is located entirely within the enclosure. In this case, the connector connects the mechanical vibrator to one of the appendages located inside the enclosure, passing through a hole in a wall of the enclosure. The system for attaching the connector to the vibrator on the one hand, and the mechanical means for supporting or guiding or measuring or controlling the temperature or the pressure on the other hand, may be identical or different, removable such as

  at least one bolt or screw, or irremovable such as a weld.

  It is preferred to use an immovable fastening system when it is located inside the enclosure, and a removable fastening system when it is located outside the enclosure. The connector preferably has the function of transmitting substantially all the

  vibration of the vibrator at the appendix without substantially modifying the frequency of these vibrations.

  A mechanical vibrator can be used for each of the appendages, or only a vibrator for several of these appendages.

  Advantageously, two or more of the totality of these mechanical means (or appendices) can be interconnected by a rigid common mechanical connection, and simultaneously connect the latter directly or indirectly to the mechanical vibrator. The rigid common mechanical connection may be disposed inside or preferably outside the thermal enclosure. It can be constituted by a rod or a rigid bar, appropriate to the ambient environment. A connector such as that described above can be used to connect the vibrator to this rigid joint mechanical connection when they are not directly connected. By proposing to apply the vibrations generated by the mechanical vibrator, possibly through a connecting piece (connector) between the mechanical vibrator and an appendix of the duct, a vibration transmission structure is obtained which is short, and small dimensions; thanks to these small dimensions, it is thus possible to minimize the diameter of the passage opening which must be provided in a wall of the thermal enclosure to allow the connecting piece to extend through it, the vibrator which is arranged outside the enclosure (with reference to this wall) until

  conduit disposed within the enclosure (with reference to this wall).

  Due to the small dimensions of this part (or structure) for transmitting vibrations, as well as thanks to the irremovable character of the mechanical connection between the appendix and the duct, for example obtained by welding or by molding, a mechanical connection can thus be obtained. between the vibrator and the vibrating conduit, which is provided with a high mechanical stiffness (static and dynamic) and a transmission part (connector) which is light; for example, the mass of the connector illustrated in FIGS. 1 to 7 may be less than 10 kilos, for example

example close to 1 to 5 kilos.

  The preferred choice of a mechanical vibrator of the electromagnetic type makes it possible to propose such vibrators whose cost is very low, which are very compact, of low mass, very robust, allowing continuous operation and capable of applying to the conduit by the intermediate of the appendix and if necessary of the connector, relatively large forces, for example of the order of a few tens of newtons.5 In this type of mechanical vibrator powered by alternating current with permanent magnet biasing, the force supplied by the alternating magnetic field is used to produce an oscillatory displacement in a given direction and the working frequency (i.e. the frequency of the vibrations produced) is equal to the electric power supply frequency, which is preferably adjustable or variable in frequency and voltage, providing for supplying this electromagnetic vibrator with an inverter or variator ator. By proposing to apply a vibration resulting from a force whose modulus i5 is adjustable, and preferably whose direction is also adjustable, it is possible to obtain a vibration of the duct with a necessary amplitude and sufficient to reduce or avoid depositing by-products on the inner walls of the tube or duct disposed in the thermal chamber; the means described above make it possible to adjust the frequency of excitation or of vibration of the duct as a function of the natural frequencies of the tube or duct and those of the vibration transmission part; this adjustment of vibration in an adjustable manner, in terms of modulus as well as of frequency and direction, is particularly favored by the characteristics of

the invention.

  The enclosure may contain a tube or multiple tubes having a single inlet and a fluid outlet, i.e., a single pass; the chamber may also contain several sets of several tubes, each having an individual inlet or common to several tubes for the fluid, each tube also having an individual fluid outlet or common to several tubes; the enclosure may contain two to four serpentine shaped tubes, each having an individual inlet for each tube and an individual or common outlet for several tubes; the chamber can be heated by burners which can be arranged in the lower part (in an area sometimes called "sole") and / or along one or more sides; it is advantageous for the burners to be arranged perpendicularly to the longitudinal axis of the rectilinear tube portions and / or perpendicular to a plane containing the longitudinal axes of different straight sections of tubes; the burners may also be arranged so that their flame extends along axes parallel to the axes of the rectilinear portions of tubes, the flame axis being collinear or spaced apart from the axes of the rectilinear portions of tubes; the enclosure may be constituted by a cracking furnace, such as a hydrocarbon steam cracking furnace, which may be gaseous at room temperature or liquid, such as naphtha; such products and methods of cracking heat treatment are described in International Application WO 92/11931 which is hereby incorporated by reference; the enclosure can also be used as a heat exchanger for heating

  or cool a fluid flowing in the conduit.

  The duct may comprise one or more rectilinear portions, for example from two to twenty straight portions, which are connected in parallel or in series and separated by at least one elbow which may be a quarter turn or a bend at 180; the rectilinear sections of tube may extend parallel to each other; in this case, several (for example from two to six) straight portions may be at least partly connected to a common collector, which may be

  located outside, and preferably inside the enclosure.

  According to a particular embodiment, the conduit comprises at least two or preferably at least three and at most twenty straight portions of tubes, each separated by a bend extending substantially over 180, so that the flow of fluid flowing in the led reverses its direction at each elbow with respect to a fixed reference, such as a partition of the enclosure; the conduit in this case a preferred form of coil or bundle; the rectilinear portions of the tube may be arranged horizontally or vertically, and some portions may be arranged vertically, while others are arranged horizontally, which are shorter than the rectilinear portions arranged vertically, the ratio of the length of the short sections to the length of the long rectilinear sections, being for example of the order of 0.05 to 0.2; where the rectilinear portions of the tube and / or the elbows may have different diameters; preferably, the rectilinear portions of tubes and the bends have an identical diameter; alternatively, the diameter of the tube may vary along this tube and / or duct, from an inlet section to an outlet section, gradually or degressively; the rectilinear portions of the tube may have a length of between 2 and 25 meters, for example

between 5 and 20 meters.

  The connector, that is to say the mechanical structure of vibration transmission produced by the vibrator to one or more appendages of the conduit, is disposed between the vibrator and the appendix; the appendix is attached or integral to a portion of the conduit, and more

  particularly integral to a conduit bend.

  The many advantages provided by the invention will be better

  understood through the following description which refers to the drawings

  annexed, which illustrate, without any limiting

  preferential embodiments of the invention.

  Unless otherwise indicated, identical numerical references in

  the different figures denote identical or similar elements.

  FIG. 1 is a diagrammatic cross-sectional view, through a vertical plane, of a thermal hydrocarbon cracking apparatus comprising an oven equipped with burners and equipped with a system for vibrating the pipe, in which hydrocarbons for cracking reaction, according to the invention, and is a

view according to B-B 'of Figure 3.

  FIG. 2 illustrates, in the same manner as FIG. 1 and on an enlarged scale, an embodiment of the means for setting

vibration of the duct.

  FIG. 3 is a diagrammatic sectional view in a vertical plane of the apparatus of FIG. 1, and is a view along AA 'of FIG. 1. FIG. 4 is a view along G of FIG. enlarged scale. FIG. 5 is a diagrammatic sectional view of the vibration transmission structure of FIGS. 1 to 4, on an enlarged scale, and

  is also a view along G of Figure 1.

  FIG. 6 is a view along F of FIG.

  FIG. 7 is a diagrammatic perspective view of a duct comprising three identical generally U-shaped tubular portions which are arranged side by side and each equipped with a respective support,

  the three supports being connected to a single vibrator.

  FIG. 8 is a diagrammatic elevational view of a serpentine shaped duct, an elbow of which carries an appendage serving as a measurement; Figure 9 illustrates on an enlarged scale with a view to

  cut in a vertical plane, the elbow and appendix of Figure 8.

  FIG. 10 illustrates in the same manner as FIG. 9 a variant of the invention in which an elbow is equipped with a means of

  guide constituting an appendage used in accordance with the invention.

  With reference to FIGS. 1 to 6, in particular, a hydrocarbon steam cracking furnace is used to manufacture olefins, schematically described in FIGS. 1 and 3 (according to orthogonal sections B-B 'and A-A'). Figures 2 and 4 respectively show a detail of Figures 1 and 3 around the bend 11 of the duct 4 and in particular the mechanical suspension means 14 and the vibration device. The furnace comprises a thermal enclosure 1 delimited by a wall 2 of refractory material, a series of burners 3 disposed along this wall and in particular on the side walls 41, 42 and the bottom 43 of the furnace. A series of several parallel ducts not shown in Figures 1 to 4 through the chamber 1. Only a duct 4 is shown schematically. The conduit 4 consists essentially of a succession of rectilinear sections of tube 5, 6, 7, 8 interconnected by curvilinear sections of tube or bends 9, 10, 11 extending over 90. The duct 4 has essentially the shape of a "U" as shown in FIG. 1. The vertical branches 5 and 7 (of respective longitudinal axis 25, 27) and the horizontal branch 6 (of longitudinal axis 26) of the "U" shaped conductors have lengths of 47, respectively, close to 12 meters, 12 meters and 1.5 meters. The internal diameter of the duct and its thickness are respectively about 48 millimeters and about 5 millimeters. The hydrocarbons subjected to steam-cracking flow into the conduit 4 in "U" penetrating therein according to the arrow 12 in Figure 1 and leaving there according to the arrow 13 in Figures 3 and 4. At the end of the portion of the conduit in "U" shape (Figure 1), the conduit forms a bend 11 at an angle of 90 relative to the plane formed by the "U" in Figure 1, and thus continues as shown in Figure 3 by the straight section of tube 8 of longitudinal axis 28

substantially horizontal.

  In the bend 11 is disposed a mechanical suspension means 14 for supporting the conduit 4 and forming an appendix thereof, and connected to a fixed support 15 disposed outside the enclosure 1, by

  via a mechanical suspension 16 such as a spring.

  The mechanical suspension means 14 essentially consists of a triangular metal piece, as shown schematically in FIGS. 3 to 5. FIG. 5 shows a detail of FIG. 4 relating to the vibrator, the connector and their attachment means. This mechanical means 14 comprises an outer portion 17 disposed outside the enclosure 1 and which thus emerges from the enclosure through an orifice 18 drilled in the wall 2 of the enclosure. At the outer part 17 of the mechanical suspension means, a rigid mechanical connector 19 (itself constituted by the assembly of metal parts illustrated in FIGS. 5 and 6) connected to a mechanical vibrator 20 is fixed with bolts and 21. Details of the connector 19 and its fastening means 21 appear more clearly in Figures 4 to 6. The length 22, the width 23 at the base and the thickness 24 of the metal plate 14, 17 of substantially triangular constituting essentially the mechanical means of suspension are respectively 800, 220 and 20 millimeters. The length 30, the width 32 and the thickness 31 of the connector 19 are respectively 70 millimeters, millimeters and 10 millimeters. The mechanical vibrator 20 essentially produces vibrations along a horizontal axis 33 perpendicular to the axis 27, along which the section of the tube 7 and the metal appendix 14 extends. With reference to FIGS. 4 to 6, the appendix 14 is provided in its upper part 17 with an orifice 45 (of axis 46) through which the spring 16 of

  duct support is attached to the appendix.

  The connector 19 consists essentially of a clevis or jaw 34 welded (weld 40) in the upper part 17 of the appendix 14; this yoke is extended by a plate 35 of rectangular shape, itself fixed by bolts 21 to a second plate 36 which faces it; a flange 37 is welded to one end of the plate 36; the vibrator 20 is fixed to this flange 37 by a second flange 38 which it is provided and by means of screws 39, and is thus mounted in a door at

  false (or suspended) in Appendix 14, 17.

  In the industrial conditions of steam-cracking of hydrocarbons, in particular naphtha, the pipe 4 is heated by the burners 3 in the chamber 1, so that the mixture is at a temperature ranging from 650 to 830 C between the inlet and the output of the speaker. The mixture of naphtha and water flowing in line 4 is in a naphtha / water weight ratio of 100/40. During the steam cracking reaction, the vibrator 20 via the connector 19 and the mechanical suspension means 14, transmits a vibration of a frequency in the range of 40 to 65 Hertz to the conduit 4 which is thus subjected to a vibration transverse mechanics under this frequency. The amplitude of the vibration, measured along the longitudinal axis 33 of the vibrator 20, is of the order of 1/10 of a millimeter. Under these conditions, it is observed that the coke deposit inside the duct 4 is

  very greatly reduced, so that the furnace stops for decoking are much more spaced over time.

  In an alternative embodiment illustrated in FIG. 7, the operation is carried out exactly as described previously with reference to FIGS. 1 to 6, except that several conduits 4 in parallel, for example three ducts 4 as schematically represented in "cavalier" perspective in FIG. 7, pass through the enclosure (not shown). These ducts 4 are all identical to those described above. A difference with the previous example is that the vibrator 20 is not connected to a single mechanical suspension means 14 through the connector 19, but to several (in this example, three) mechanical means 14 respective suspension of each of the conduits 4, which are connected together by a rigid common mechanical connection 29, in the form of a mechanical rod securely attached to all these mechanical means 14, itself connected to the vibrator 20 via the connector 19, and a rigid connection 48 of said

connector 19 to said rod 29.

  Under these conditions, only one vibrator is used to vibrate several conduits 14 at the same time; we observe the same

  way a low coke deposit in all of these ducts.

  With reference to FIGS. 8 and 9, the operation is carried out in a hydrocarbon steam cracking furnace for producing olefins, schematically described in FIG. 8, which shows a pipe 4 in the form of a coil 52 consisting essentially of connected rectilinear sections. by bends 11 to 180 and disposed in a thermal chamber consisting of a furnace 1 comprising a zone 51 of radiation and burners (not shown). The duct comprises in one of its elbows 11 a "thermometric well" 50 in the form of a rigid cylindrical sheath 56 of longitudinal axis 54, whose closed end 53 enters the bend 11, and comprising the inside the sheath one

thermocouple 58.

  The sleeve 56 emerges from the enclosure of the furnace 1 through an orifice 18 open through the wall 2 of the enclosure. The part of the sheath 56 external to the furnace is connected to a mechanical vibrator 20 via a rigid connector 19 and bolts and screws 21. FIG. 9 schematically shows the bend 11 of the duct, the "thermowell" 50, the sheath 56, the thermocouple 58, the mechanical vibrator 20, the rigid connector 19 and the bolts and screws 21. Preferably, a metal part 57, of substantially triangular shape5 is fixed by welds 59 to the elbow 11 and the sleeve 56 to return

  the whole more rigid and solidary.

  The mechanical vibrator 20 is an electromagnetic vibrator and

  produces transverse vibrations along the axis 33.

  In the hydrocarbon steam cracking industrial conditions mentioned above and during the steam cracking reaction, the vibrator 20 via the connector 19 and the sheath 56, transmits a vibration of a frequency in the range of 65 Hertz at conduit 1, which is thus subjected to transverse mechanical vibration under this frequency. (Amplitude of the vibration: of the order of 1/10 of a millimeter). Under these conditions, it is observed that the coke deposit inside the duct 4 is very greatly reduced, so that the decoking stops are more

spaces over time.

  The duct 4 is made of a material such as a steel specially chosen for particular resistance to high temperatures (for example of the order of 500 C to 1150 C or even 1500 C) prevailing in the enclosure; the various elements (elbows 11 and straight sections 5 of tubes) constituting the duct 4, are generally assembled together by welds, such as those shown schematically in FIG. 10 and labeled 40, which are provided at the interface or junction between

  the end 64 of the straight sections 5, and the elbow 11.

  In the alternative embodiment shown in FIG. 10, the alternating forces applied to the appendix 60 by the vibrator 20 are directed along an axis 33 extending preferably radially with reference to

  the longitudinal axis 54 of Appendix 60.

  In this embodiment, the appendix 60 and the bend 11 constitute a single metal part; this part comprises a first portion forming the walls 62 of the bend 11, a second portion (central) 61 of connection and a third portion 63 of rod-shaped end which extends through the orifice 18 provided in the wall 2 of

  oven; this portion 63 cooperates with the orifice 18 to guide the bend (and the duct) in its movements due to the expansion of the duct under5 effect of the temperature in the oven.

  The electromagnetic vibrator can be chosen from those proposed by BINDER MAGNETE GMBH (Mönchweilerstrasse 1, Postfach 1220, D-7730 Villingen-Schwenningen, Germany). The power inverter of the vibrator can be chosen

  among those proposed by TELEMECANIQUE.

  In the embodiments illustrated in FIGS. 8 to 10, the vibration application axis 33 is parallel to (for example, coincident with)

  a plane containing the longitudinal axes of straight pipe sections of the coil; in another variant (not shown), this axis 33 may be inclined relative (for example perpendicular) to this plane.

Claims (19)

  1. A method of vibrating a conduit (4) to reduce or prevent deposition of solid particles on the inner wall of said conduit in which flows one or more fluids, which conduit is disposed in part at least in a chamber thermal device (1), a method in which a transverse vibration produced by a mechanical vibrator (20) which is arranged outside the thermal enclosure, in which said vibration is transmitted via an appendage, is applied to the duct; (14, 60) forming part of a mechanical means for supporting or guiding said conduit or a   measuring instrument attached to said conduit.   2. The method of claim 1 wherein said appendix (14, 60) consists essentially of one or more metal parts (s) fixed (s) rigidly and irremovably to one or more walls of said conduit, preferably welded to a wall of said conduit or constituting a single piece with a portion of the walls of said conduit, which appendix is preferably of elongate shape, for example essentially consisting of a tube section or bar.   The method of claim 1 or 2, wherein said   vibrator (20) is connected directly to said appendix.   The method of claim 1 or 2, wherein said vibrator (20) is indirectly connected to one or more appendages by   via a connector (19) adapted to transmit said vibration.   5. Process according to any one of claims 1 to 4   wherein the vibrations are applied by exerting a force in a substantially transverse or radial direction (33) with reference to   the longitudinal axis (27) of a rectilinear section of said duct.   The method of any one of claims 1 to 5, wherein said vibrator is removably attached to said   connector or said appendix, for example by at least one screw or bolt.   7. Method according to any one of claims 1 to 6,   wherein an electromagnetic vibrator powered by a variable frequency power source is used.   Process according to any one of claims 1 to 7,   in which vibrations are applied to said conduit at a frequency   less than 1000 hertz, preferably between 10 and 100 hertz.   Apparatus for applying transverse vibrations produced by a mechanical vibrator (20) to a conduit (4), at least a portion of which extends inside a thermal enclosure (1), which apparatus comprises a fastening means Rigid mechanics of the vibrator at a prominent projection (14, 60) of the duct, which appendix is part of a mechanical means of support or guidance   said conduit or a measuring instrument attached to said conduit.   Apparatus according to claim 9, wherein said vibrator is indirectly connected to one or more appendages by   via a connector (19) adapted to transmit said vibration.   Apparatus according to any of claims 9 to 10   which comprises several vibrators respectively fixed or connected to one or   several appendix (s) of said conduit.   Apparatus according to any one of claims 9 to   11, wherein said vibrator is removably attached to said connector or said appendix, for example by at least one screw or bolt.   Apparatus according to any one of claims 9 to 12,   wherein said vibrator is an electromagnetic vibrator powered by a variable frequency power source, preferably powered by a frequency and voltage converter, and is   preferably capable of applying vibrations to said duct at a frequency below 1000 hertz, preferably between 10 and 100 hertz.   Apparatus according to any one of claims 9 to   13, wherein said vibrator is suspended from said connector or said appendix, and preferably the mass of said vibrator is less than or equal to 20 kilos, and preferably the vibrator is disposed at a small distance from an orifice (18) provided in a wall of the thermal enclosure   and through which extends said appendix.   15. A device for heat treatment of one or more fluids which comprises: - a thermal enclosure (1), - a conduit (4) in which said fluid or fluids flow, which extends in part at least to the inside said enclosure, and which comprises a projection (14, 60) protruding from the conduit, which appendix is part of a mechanical means for supporting or guiding said conduit or a measuring instrument fixed to said conduit, - a vibrator mechanical assembly (20), disposed outside the enclosure, thermal,   a mechanical connection means connecting said appendix to said vibrator.   16. Apparatus according to claim 15 which comprises a   Apparatus according to any one of claims 9 to 14.   17. Device according to any one of claims 15 to   16, wherein said appendix is fixed or incorporated in a bend (11), forming part of said duct.   18. Device according to any one of claims 15 to   17, wherein said appendix is elongate and extends substantially   parallel to the longitudinal axis (27) of a rectilinear section (7) of tube forming part of said duct.   19. Device according to any one of claims 15 to   18, wherein said appendage consists essentially of a rod or a tube extending through an orifice (18) provided in a wall forming part of the means delimiting the thermal enclosure, which appendix is fixed or integrated in a bend (11) disposed at one end of a straight pipe section of said conduit, and wherein said straight pipe section and said appendix extend substantially horizontally or vertically.