EP3465065B1 - Heat exchanger equipped with a filtering element - Google Patents

Description

The invention relates to a heat exchanger, in particular a tube heat exchanger. The exchangers of the present invention are particularly suitable for use in industrial units, in particular refineries. US 2008/0271874 A1 discloses a heat exchanger according to the preamble of claim 1.

Tubular heat exchangers frequently experience blockages resulting from the accumulation of solid elements entrained by the fluids to be cooled. These solid elements can result from corrosion of the materials of the exchanger or of the fluid supply pipes or can be scale or objects forgotten during maintenance. When a blockage occurs in an exchanger of an industrial unit, its maintenance often requires the complete shutdown of the unit and the opening of the exchanger for cleaning. When these exchangers are large, this cleaning requires the use of equipment when opening the exchanger and is relatively long.

In order to delay the fouling and clogging of the exchangers, it is known practice to place a filter upstream of the tubes of the exchanger. This filter extends over the entire section of the casing and is generally fixed to the casing of the exchanger by fixing flanges fixed to a rim of the casing so that it is necessary to open the latter. ci to extract the filter and clean or replace it. It is also necessary to attach the cleaned filter or the new filter to the casing before closing it and restarting the unit, which takes time. Thus, if the maintenance periods can be spaced out, there is a need to further reduce the duration of the maintenance period.

To this end, the object of the invention relates to a heat exchanger comprising a casing containing an assembly of heat exchange elements in the form of tubes defining at least two independent fluid circulation circuits, the casing comprising in in addition to at least one filter element associated with a fluid circuit and arranged inside the casing between an inlet opening of the casing and an inlet face of the fluid in a fluid circuit. According to the invention, the filter element is planar and the heat exchanger further comprises at least one support element now one face of the filter element at a predetermined distance from said inlet face, substantially parallel or parallel thereto. The support element bears against said face of the filter element or against said inlet face, optionally without securing between the bearing element and said face, in particular without securing the filter element to the shell, assembly or other element of the heat exchanger.

Thus, the filter element is supported, in other words supported, by the support means or means, preferably without joining, which makes it possible to put it in place and extract it easily and quickly. The support between the filter element and the support element or between the support element and the inlet face thus preferably results solely from terrestrial gravity.

The filter element can nevertheless be secured to the casing and held in position by a fixing device, in particular temporary, for example of the bayonet type.

The invention is particularly suitable for heat exchangers between liquid fluids.

Advantageously, the filter element is shaped to retain solid particles present in a fluid, and in particular to separate solid particles present in a liquid.

The term “fastening” is understood to mean a fastening, definitive or temporary, which does not allow movements, such as fastening by rivets, by screw-nut systems or by welding or gluing. In other words, the support elements according to the invention are not screws or rivets and the heat exchanger according to the invention is preferably devoid of elements for fixing the filter element and.

Advantageously, said at least one support element can be chosen from a support element integral with the casing, a support element integral with the inlet face, a support element integral with the filter element. In the latter case, the support element preferably bears against the face of the fluid entering the circuit. The heat exchanger may include one or more of each of these backing elements to support the filter element.

In particular, support elements can be arranged on either side of the filter element.

According to the invention, at least one support element can be disposed at a distance from a peripheral edge of the filter element. This can help maintain the filter element and limit its deformation. Other support elements can advantageously be placed near the peripheral edge of the filter element.

Advantageously, said at least one support element is in the form of a rod or a rib. Such supports have the advantage of limiting the disturbances of the circulating fluid. They can advantageously be arranged substantially parallel to the direction of circulation of the fluid, generally substantially perpendicular to the inlet face of the fluid circuit.

Advantageously, at least one support element can be a rib integral with the casing and on which the filter element rests on at least part of its periphery.

• une nervure s'étendant sensiblement parallèlement ou parallèlement à la face d'entrée du circuit de fluide et recevant l'élément filtrant en appui sur une face parallèle à la face d'entrée,
• une nervure s'étendant sensiblement perpendiculairement ou perpendiculairement à la face d'entrée du circuit de fluide, une extrémité de la nervure distante de la face d'entrée reçoit en appui l'élément filtrant.

It is possible to provide one or more ribs chosen from:

• a rib extending substantially parallel or parallel to the inlet face of the fluid circuit and receiving the filter element resting on a face parallel to the inlet face,
• a rib extending substantially perpendicular or perpendicular to the inlet face of the fluid circuit, one end of the rib remote from the inlet face receives the filter element in support.

Advantageously, at least one support element can be a support foot, one end of which is integral with the filter element, or of the inlet face, and the other end of which bears against the inlet face, or receives the filter element in support, respectively.

In particular, a support foot may extend substantially perpendicular or perpendicular to the inlet face and may have one end integral with the filter element, or with the inlet face, and another end resting against the face of inlet, or receiving the supporting filter element, respectively.

A single foot may be in the form of a sleeve. As a variant, at least two support feet, preferably at least three, may be provided, the feet being in the form of rods, or even of plates, preferably in the form of rods.

Advantageously, the support leg (s) can bear against the casing, in particular against its internal face. This can promote the maintenance of the filter element, in particular when the latter is in a substantially vertical position, one or more support feet resting on the casing preventing the tilting of the filter element. The support foot (s) can then advantageously have a shape that complements the envelope, in particular its internal face.

Advantageously, at least one of said at least one support element and the filter element can be movable between an active position in which said at least one support element bears against the filter element or against the face. inlet and an inactive position in which said at least one support element does not bear against the filter element or against the inlet face. The passage from one position to another can be obtained by a rotation, a translation, or a combination of these movements.

Such an arrangement can allow cooperation by supporting the support element and the filter element or the support element and the inlet face in a particular position of the support element or the 'filter element corresponding to the active position. This can make it possible to prevent a tilting of a substantially vertical filter element. This arrangement has the advantage of being simple to implement, inexpensive and of allowing rapid coupling of the filter element to the casing.

Advantageously, the filter element of the exchanger according to the invention can also be in several parts associated by removable fixing means or in several articulated parts. This can make it possible to facilitate cleaning of the filter element and can make it possible to easily extract the filter element, in particular through an opening in the envelope, without having to open the envelope.

The heat exchange elements of the exchanger according to the invention are tubes. Advantageously, the inlet face of one of the fluid circuits extends substantially perpendicularly to the axes of the tubes. The entry face can then be defined as a flat surface containing the openings of the tubes and the contour of which matches the internal shape of the envelope. The filter element is preferably kept away from this inlet face, the fluid circulating inside the tubes.

For a heat exchanger of this type, the filter element advantageously has an open area greater, in particular by at least 50%, than the sum of the pass areas of the tubes. By open surface is meant the pass-through surface of the filter element, in other words the surface through which a fluid can flow through the filter element.

Advantageously, the filter element can have a plurality of meshes or perforations, each mesh or perforation having an open surface (S1) less than an open surface (S2) of a heat exchange element, the most internal dimension. large of a mesh or perforation being less than the largest internal dimension of a heat exchange element.

In general, the filter element, positioned parallel to the inlet face, inside the casing, can be of the same shape and dimensions as a surface or a section of the inlet face. Advantageously, the filter element comprises a peripheral edge in contact with an internal face of the envelope, possibly with a sufficiently small clearance to prevent the passage of fluid or particles between the internal face of the envelope and the peripheral edge.

The invention also relates to an industrial unit comprising at least one heat exchanger according to the invention. This industrial unit is advantageously a refinery unit.

The invention finally relates to a method of heat exchange between two fluids, in which the fluids are circulated in a heat exchanger according to the invention, one of the fluids being chosen from water and hydrocarbons, the other fluid being chosen from water, air and hydrocarbons.

• la figure 1 est une représentation schématique d'un échangeur de chaleur selon un mode de réalisation de l'invention ;
• la figure 2 est une vue partielle de face d'un élément filtrant ;
• les figures 3 et 4 sont des représentations en perspective d'éléments filtrants pourvus d'éléments d'appui selon différents modes de réalisation ;
• les figures 5, 6a et 7 sont des vues en coupe longitudinale d'un échangeur de chaleur du type de la figure 1 présentant un élément filtrant maintenu par des éléments d'appui selon d'autres modes de réalisation ;
• la figure 6b est une vue de face de l'élément filtrant et de l'enveloppe représentés figure 6a ;
• la figure 8 est une vue de face d'un élément filtrant selon un autre mode de réalisation.

The invention is now described with reference to the appended non-limiting drawings, in which:

• the figure 1 is a schematic representation of a heat exchanger according to one embodiment of the invention;
• the figure 2 is a partial front view of a filter element;
• the figures 3 and 4 are perspective representations of filter elements provided with support elements according to different embodiments;
• the figures 5, 6a and 7 are views in longitudinal section of a heat exchanger of the type of the figure 1 having a filter element held by support elements according to other embodiments;
• the figure 6b is a front view of the filter element and the envelope shown figure 6a ;
• the figure 8 is a front view of a filter element according to another embodiment.

Identical references can be used to designate identical or similar elements from one figure to another.

By substantially horizontal, longitudinal or vertical is meant a direction / a plane forming an angle of at most ± 20 °, or even at most 10 ° or at most 5 ° with a direction / plane that is horizontal, longitudinal or vertical.

By substantially parallel, perpendicular or at right angles is meant a direction / an angle deviating by at most ± 20 °, or even by at most 10 ° or by at most 5 ° from a direction parallel, perpendicular or from a right angle.

The figure 1 shows a heat exchanger 10 comprising a casing 12 which contains an assembly 14 of heat exchange elements 16.

In the example shown figure 1 , these heat exchange elements 16 are tubes arranged parallel to each other. These tubes are arranged so as to allow a circulation of a first fluid F1 inside them and a circulation of a second fluid F2 between the tubes. The assembly 14 of heat exchange elements 16 thus defines a first circulation circuit for a fluid F1 inside the heat exchange elements 16 and a second circulation circuit for the fluid F2. The fluid F1 enters the first fluid circuit via an inlet face 18. This inlet face 18 extends substantially perpendicularly to the axes of the tubes 16 and can be defined as a flat surface containing the openings of the tubes and whose contour follows the internal shape of the envelope.

The heat exchanger 10 further comprises a filter element 20 which is arranged inside the casing 12 between the inlet face 18 and an inlet 22 made in the casing 12 for the entry of the fluid F1. This filter element 20 has a peripheral edge 20a the outline of which matches the internal face 13 of the envelope. There may be a clearance between this peripheral edge 20a and the internal face 13, a sufficiently small clearance to prevent the passage of particles between the peripheral edge 20a and the internal face 13 of the casing.

It will be noted that the fluid F1 leaving the first fluid circuit leaves the casing 12 through an opening 24. The second fluid F2 enters the casing 12 through an opening 26 and leaves it through an opening 28. The circulations of the fluids F1 and F2 are represented by arrows on the figure 1 .

The filter element 20 is maintained at a predetermined distance from the inlet face 18 of the first fluid circuit by at least one support element 30. Thus, when in the solid manner is brought by the fluid F1 inside of the casing 12, it is retained by the filter element 20 and does not penetrate inside the tubular heat exchange elements 16 of the assembly 14. This makes it possible to avoid their clogging. Further, even when a portion of the filter element 20 becomes clogged with this material, fluid can continue to pass past the filter element 20 and can enter all of the heat exchange elements 16. so that the heat exchanges with the fluid F2 are not disturbed. Finally, if the filter element 20 is blocked, the latter can be cleaned or easily extracted from the envelope. In particular, the fact that the filter element is not rigidly fixed to the casing but is only supported via one or more support elements 30 makes it possible to facilitate the assembly / disassembly of the filter and to reduce the assembly / disassembly time. . The distance between the filter element 20 and the inlet face 18 may be chosen according to the dimensions of the heat exchanger and possibly according to the nature of the fluids. For a filter element of about 2 meters in diameter, this distance may be of the order of 5 to 10 cm. More generally, the distance can be of the order of 2 to 4 times the diameter of the tubes 16.

In general, whatever the shape of the heat exchange elements 16, the filter element 20 is flat and may be in the form of a mesh or grid, as visible. figure 2 , or in the form of a perforated flat plate.

In the present embodiment, the filter element has a shape and dimensions substantially identical to a section of the casing 12, which makes it possible to position it inside the casing, substantially parallel to the inlet face 18. In other words, the filter element 20 is of the same shape and dimensions as the surface of the face inlet 18. Here, the total open area of the filter element 20, which corresponds to the area of passage of a fluid through the filter element, is greater than the total open area of the filter elements. tubular heat exchange 16, in other words the sum of the internal sections of the tubes 16. The open area of the filter element 20 is preferably high enough to limit the pressure drops.

On the figure 2 , the surface S1 represents the open surface of a mesh or perforation of the filter element 20 while the surface S2 represents the open surface of a tube 16 of the assembly 14. Each mesh or perforation preferably has an open surface. SI less than the open area S2 of a tube 16.

Further, the largest internal dimension of a mesh or perforation of the filter element 20 is preferably less than the internal diameter of the tubes, eg 10% (approximately).

The support element or elements 30 making it possible to support the filter element 20 at a distance from the inlet face 18, parallel or substantially parallel thereto, may have various and varied shapes, some of which are described below. with reference to the figures.

In the embodiment shown figure 1 , several support elements 30 are provided, each support element being in the form of feet 301, one end of which is integral with the filter element 20 and the other end of which bears against the inlet face 18 A filter element 20 of this type is shown in the figure. figure 3 . Some of the feet 301 are integral with the periphery of the filter element 20, so that they bear against the internal face 13 of the casing 12 when the filter element 20 is placed inside the casing , as shown figure 1 . This arrangement makes it possible to avoid tilting of the filter element 20, in particular when the latter is in a substantially vertical position. Another foot 301 is disposed substantially in the center of the filter element 20. The number of feet 301 and their shape can be chosen as long as they allow the filter element 20 to be supported at a distance from the face. input 18, substantially parallel thereto. In addition, as shown, one or more feet may be integral with the filter element 20 at a point remote from the peripheral edge 20a, to avoid deformation of the filter element.

In a variant not shown, these feet 301 could be secured to the entry face 18. Similarly, they are preferably attached near or along the internal face 13 of the casing 12 but could also be arranged at a distance. of this for a better maintenance of the filter element.

In the embodiment of the filter element 20 shown in figure 4 , a single support element 302 in the form of a sleeve extends over the entire periphery of the filter element 20, forming a support element integrated into the filter element 20. In an embodiment not shown, this element support 302 could be of smaller dimensions. As a variant, a support element 302 of this type could be secured to the inlet face 18, and not to the filter element 20.

In the embodiment shown figure 5 , the support elements 30 comprise two ribs 303 integral with the internal face 13 of the casing 12. These ribs 303 extend substantially parallel to the inlet face 18, so as to receive and rest against one of their face the filter element 20. Two or more ribs 303 may be distributed over the internal face 13 of the casing 12. In a variant not shown, a single rib 303 may extend over the entire periphery of the casing 12.

In the embodiment shown in figures 6a and 6b , other ribs 304 are provided on the internal face 13 of the casing 12, integral with the latter. These ribs 304 are arranged so as to receive in abutment a face of the filter element 20 opposite to the face bearing against the rib or ribs 303. These ribs 304 may be in the form of tabs, cooperating with corresponding notches 21. of the filter element 20, as shown in figure 6a (In this figure, the distance between casing 12 and the periphery of filter element 20 has been exaggerated for clarity). This allows the filter element 20 to be translated into the casing until it rests against the ribs 303, the filter element 20 being positioned so that the ribs 304 coincide with the ribs. notches 21. As for a bayonet type attachment, it is then sufficient to pivot the filter element 20 according to the arrow shown. figure 6b to obtain an angular offset between the ribs 304 and the notches 21 thus ensuring maintenance of the filter element 20, even if the latter is in a vertical position, by resting its opposite faces against the ribs 303 and 304.

Of course, the invention is not limited by a particular number of ribs 304, a single rib can be provided or more than two if necessary.

In the embodiment shown figure 7 , ribs 305 are integral with the internal face 13 the casing 12 but extend substantially perpendicularly to the inlet face 18, so that their end 306 remote from the inlet face 18 receives the filter element in support 20. The number of these ribs 305 can be variable, for example two, preferably three, or even more.

The invention is not limited by the number and shape of the support elements 30. It is also possible to provide for one or more support elements to be mobile in rotation or in translation. For example the support element 301 shown figure 3 can be articulated to the filter element 20 or be secured to the latter by temporary fixing means, which can facilitate handling of the filter element. Ribs integral with the casing can also be connected to the casing so as to be movable between an active position, resting against the filter element and an inactive position, allowing for example the passage of the filter element. These ribs can for example be connected to the casing by a hinge, a pivot or the like, or else be mounted to move in translation.

The various support elements described above and with reference to figures 3 to 7 can be combined and can either support one of the faces of the filter element 20 in support. In particular, support elements can be provided which receive in support opposite faces of the filter element 20, thus improving its retention, especially in a substantially vertical position. It is also possible to provide for temporary fixing of the support element (s) to the casing or to the inlet face in order to prevent any movement of the fixing element during the circulation of the fluid.

Whatever the shape and number of the support elements, the filter element 20 can also be made in several parts A, B, C, D, E, F, G, H, J, as shown. figure 8 . This makes it possible to facilitate its extraction from the casing 12. These various parts AJ can be associated by removable or temporary fixing means, such as for example clipping systems, interlocking systems, screws or the like, or can be articulated to each other so that they can be folded over one another and facilitate the movement of the filter element.

This makes it possible to extract the filter element 20 through a relatively narrow opening, such as the opening 22 of the casing 12. Therefore, it is no longer necessary to proceed to a complete opening of the casing 12 to be extract the filter element 20 and clean it, thus reducing the duration of maintenance and the downtime of the industrial unit equipped with the heat exchanger 10.

Such an arrangement also makes it possible to change only a damaged part of the filter element. Finally, cleaning can be carried out more efficiently on parts of smaller dimensions than the filter element.

Claims (13)

1. A heat exchanger (10) comprising a shell (12) containing an assembly of heat exchange elements (16) in the form of tubes defining at least two independent fluid circulation circuits, the shell (12) further comprising at least one filtering element (20) associated with a fluid circuit and arranged inside the shell (12) between an inlet opening of the shell and an inlet face (18) of the fluid into a fluid circuit, such that the filtering element (20) is planar, the heat exchanger comprising at least one bearing element (30, 301, 302, 303, 304, 305) keeping one face of the filtering element at a predetermined distance away from said inlet face, substantially parallel thereto, the bearing element bearing against said face of the filtering element or against said inlet face, without any means of connection between the bearing element and said face, characterized in that the heat exchanger comprises at least one bearing element arranged at a distance away from a peripheral edge (20a) of the filtering element (20).
2. The heat exchanger (10) according to claim 1, characterized in that said at least one bearing element (30, 301, 302, 303, 304, 305) is selected from a bearing element connected the shell, a bearing element connected to the inlet face, and a bearing element connected to the filtering element.
3. The heat exchanger (10) according to either one of claims 1 or 2, characterized in that said at least one bearing element is in the form of a rod or a rib.
4. The heat exchanger (10) according to any one of claims 1 to 3, characterized in that at least one bearing element (303, 304, 305) is a rib which is connected to the shell and on which the filtering element rests over at least part of its periphery.
5. The heat exchanger (10) according to claim 4, characterized in that said at least one rib (303, 304, 305) is selected from:

   - a rib extending substantially parallel to the inlet face of the fluid circuit and receiving the filtering element in a manner bearing against a face parallel to the inlet face,

   - a rib extending substantially perpendicular to the inlet face of the fluid circuit, one end of which rib, which end is remote from the inlet face, receives the filtering element in abutment.
6. The heat exchanger (10) according to any one of claims 1 to 5, characterized in that at least one bearing element (301, 302) is a support leg, one end of which is connected to the filtering element, or the inlet face, and the other end of which bears against the inlet face or receives the filtering element in abutment, respectively.
7. The heat exchanger (10) according to claim 6, characterized in that said at least one support leg bears against the shell.
8. The heat exchanger (10) according to any one of claims 1 to 7, characterized in that at least one of said at least one bearing element and the filtering element is movable between an active position, in which said at least one bearing element bears against the filtering element or against the inlet face, and an inactive position, in which said at least one bearing element does not bear against the filtering element or against the inlet face.
9. The heat exchanger (10) according to any one of claims 1 to 8, characterized in that the filtering element (20) is formed of a plurality of parts (A-J) connected by removable fixing means or is formed of a plurality of articulated parts (A-J).
10. The heat exchanger (10) according to any one of claims 1 to 9, characterized in that the inlet face (18) extends substantially perpendicular to the axes of the tubes, and in that the filtering element (20) has an open surface area greater than the sum of the passing surface areas of the tubes.
11. The heat exchanger (10) according to any one of claims 1 to 9, characterized in that the filtering element (20) has a plurality of meshes or perforations, each mesh or perforation having an open surface area (S1) less than an open surface area (S2) of a heat exchange element (16), the largest internal dimension of a mesh or perforation being less than the largest internal dimension of a heat exchange element (16).
12. An industrial unit comprising at least one heat exchanger according to any one of claims 1 to 11.
13. A method of heat exchange between two fluids, wherein the fluids are circulated in a heat exchanger according to any one of claims 1 to 11, one of the fluids being selected from water and hydrocarbons, the other fluid being selected from water, air and hydrocarbons.

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