FR2769082A1 - PLATES OF A HEAT EXCHANGE PLATE BEAM AND METHODS OF MANUFACTURING SUCH A PLATE - Google Patents

Abstract

The invention concerns a plate of an array of heat transfer plates (1), comprising a central part provided with undulations (11) and edges with smooth surface, characterised in that it is formed by at least two metal plate portions (12; 13) of different metallurgical compositions, abutted to form at least a joint face (14) and mutually connected by a continuous and sealed weld seam (15) extending over the whole length of said joint face (14). The invention also concerns methods for making this type of plates and an array of heat transfer plates comprising such a plate.

Description

 The present invention relates to a plate of a bundle of heat exchange plates.

 The present invention also relates to methods of manufacturing such a plate and a bundle of heat exchange plates.

 In certain industrial fields, such as in the field of refining or petrochemistry, it is necessary to carry out a significant heat exchange between a hot fluid and a cold fluid causing on this cold fluid temperature variations of the order of 300 at 4000C.

 Until now, in order to be able to carry out such heat exchanges, it is known to use heat exchangers formed from several tubular bundles arranged in series.

 Depending on the heat exchange to be carried out, the number of tube bundles is often from four to six and sometimes more.

 In addition, the chemical composition of fluids can vary during heat exchange taking into account temperature variations and it is necessary to adapt the materials of the tubes of the tube bundles according to these changes in order to avoid phenomena of corrosion can occur at both low and high temperatures.

 Under these conditions and depending on the fluids treated, the so-called "cold" tubular bundles comprise tubes, for example made of carbon steel, and the tubular bundles operating at high temperatures of the order of 400 to 5000 ° C., comprise tubes, for example of steel stainless.

 It is also known to use plate heat exchangers which have the advantage of having a very good heat exchange coefficient and a low coefficient of friction.

 This type of heat exchanger generally comprises bundles of plates formed by a stack of plates parallel to each other and delimiting between them a double circulation circuit of two independent fluids.

 Each plate is made of a single material which is determined according to the most severe conditions of use so as to be able to withstand high temperatures.

 This is why the plates of the plate bundles are generally made of stainless steel, which penalizes the use of such plate bundles in certain fields of application, given the cost of this material.

 Thus, plate heat exchangers are more expensive than tube bundle heat exchangers so that their economic interest is only justified if all the bundles of tubes are replaced by a single plate heat exchanger.

 The invention aims to avoid these drawbacks.

 The subject of the invention is therefore a plate of a bundle of heat exchange plates, of the type comprising a central part provided with corrugations and edges with a smooth surface, characterized in that it is formed by at least two portions of metal plate of different metallurgical compositions, placed edge to edge to form at least one joint plane and connected together by a continuous and sealed weld bead extending over the entire length of said joint plane.

According to other features of the invention
- the undulations of each metal plate extend to the joint plane to form continuous passages,
- the portions of metal plates comprise at said joint plane an edge with a smooth surface on which is fixed at least one insert covering said joint plane and comprising corrugations arranged in the extension of the corrugations of said plate portions to form continuous passages ,
the joint plane extends over the entire width of said plate or over the entire length of this plate,
the weld bead is of the through type and is produced by means of a high energy density beam or by the TIG process with or without filler metal or by the MIG or MAG process,
- at least one portion of metal plate is made of stainless steel, the chromium content of which is greater than 13%,
- at least a portion of metal plate is made of alloyed or unalloyed steel,
- At least a portion of metal plate is made of nickel alloy.

The invention also relates to a method of manufacturing such a plate from a bundle of heat exchange plates, characterized in that it consists
- placing edge to edge at least two flat metal plate portions of different metallurgical compositions to form at least one joint plane,
to make a continuous and sealed weld bead over the entire length of said joint plane,
- and to form corrugations in the central part of the plate.

According to a variant, the subject of the invention is a method of manufacturing such a plate from a bundle of heat exchange plates, characterized in that it consists
to form corrugations in the central part of at least a first portion of a flat metal plate by providing smooth edges on the edges of this first plate portion,
- To form corrugations in the central part of at least a second portion of a flat metal plate by providing smooth edges on the edges of this second plate portion, said second portion of plate having a metallurgical composition different from said first portion of plate,
placing said plate portions edge to edge to form at least one joint plane,
to make a continuous and sealed weld bead over the entire length of said joint plane,
- And to fix at said joint plane at least one insert comprising corrugations arranged in the extension of the corrugations of said plate portions to form continuous passages.

According to another variant, the subject of the invention is a method of manufacturing such a plate from a bundle of heat exchange plates, characterized in that it consists:
- placing edge to edge at least two flat metal plate portions of different metallurgical compositions to form at least one joint plane,
to make a continuous and sealed weld bead over the entire length of said joint plane,
to form corrugations in the central part of each plate portion by providing edges with smooth surfaces on the edges of said plate portions,
- And to fix at said joint plane at least one insert comprising corrugations arranged in the extension of the corrugations of said plate portions to form continuous passages.

 Finally, the subject of the invention is a bundle of heat exchange plates formed by a stack of plates each comprising a central part provided with corrugations and edges with a smooth surface and delimiting between them at least two circulation circuits of at least two independent fluids, said plates comprising, on the one hand, a heat exchange zone between the fluids and, on the other hand, at their free ends, an inlet and outlet area for said fluids, characterized in what it includes at least one plate as mentioned above.

According to other features of the invention
- the fluid inlet and outlet zones are formed by the planar ends of the plates between which independent plates are inserted and provided with reliefs to ensure the distribution of the fluids in the heat exchange zone,
- the independent plates are made of stainless steel with a chromium content of more than 13%, or of alloyed or unalloyed steel or of nickel alloy.

The characteristics and advantages of the invention will appear during the description which follows, given by way of example, and made with reference to the accompanying drawings, in which
- Fig. 1 is a schematic perspective view partially cut away of a bundle of plates according to the invention,
- Fig. 2 is a schematic top view of a first embodiment of a heat exchange plate according to the invention,
- Fig. 3 is a cross-sectional view along line 3-3 of FIG. 2,
- Fig. 4 is a schematic top view of a second embodiment of a heat exchange plate according to the invention,
- Fig. 5 is a sectional view along line 4-4 of FIG. 4,
- Fig. 6 is a schematic perspective view of a connecting insert for the plate portions making up the plate shown in FIG. 4,
- Fig. 7 is a schematic perspective view of a variant of a heat exchange plate according to the invention.

 In Fig.l, there is shown schematically a bundle of heat exchange plates, designated as a whole by the reference 1 and of generally parallelepiped shape.

In the embodiment shown in
Fig.l, the plate bundle 1 consists of three parts, a central part A and two end parts, respectively B and C.

 The central part A which constitutes the actual heat exchange zone consists of a stack of plates 10 parallel to each other.

 Each plate 10 consists of a thin sheet and comprises, in a conventional manner, edges with a smooth surface and, between these edges, undulations 11 by which they are in contact with each other and by which they delimit circuits of circulation of in dependent fluids.

 The circulation of the fluids in the bundle of plates 1 is for example cocurrent, counter-current or cross-current.

According to the embodiment shown in the
Fig. 1, the plates 10 are assembled with each other at their longitudinal edges by connecting means constituted for example by bars 2 extending over the entire length of the longitudinal edges of said plates 10 and by a solder layer 3 deposited over the entire length and over the entire height of each lateral surface of the bundle of plates 1 to form a sealed weld wall.

 The stack of plates 10 is placed between an upper plate 4 and a lower plate 5 extending over the entire surface of the plates 10 and the edges of which are connected to the edges of said plates 10 by the layers of solder 3.

 To direct the fluids which circulate in the corresponding circuits of the bundle of plates 1, this bundle of plates 1 comprises, at each of its ends, an inlet zone and an outlet zone of said fluids which constitute the end parts B and C of said bundle of plates 1.

 For this, the bundle of plates 1 comprises, at the inlet and outlet areas of the fluids, closed ends 6 and open ends 7 for these fluids flowing in the corresponding circuits.

 The closed ends 6 are closed by tongues 8 assembled to the adjacent plates 10.

 Referring now to Figs. 2 and 3, a first embodiment of a plate 10 of the bundle of plates 1 will be described.

 As shown in these figures, the plate 10 is formed, in this embodiment, by two portions of metal plate, respectively 12 and 13, of different metallurgical compositions.

 These plate portions 12 and 13 are placed edge to edge to form a joint plane 14 and are interconnected by a continuous and sealed weld bead 15 extending over the entire length of this joint plane 14.

 In this embodiment, the corrugations 11 of each portion of metal plate 12 and 13 extend to the joint plane 14 to form continuous passages for the corresponding fluids.

 The joint plane 14 extends over the entire width of the plate 10.

 According to a variant, and more particularly in the case of a circulation of cross-current fluids, the joint plane 14 can extend over the entire length of the plate 10.

 The ends of the plate 10 corresponding to the inlet and outlet zones of the fluids are provided with end plates, respectively 30 and 31, provided with reliefs 30a and 31a which make it possible to channel the corresponding fluid in the circuits of the bundle of plates 1.

 The manufacture of the plate 10 is carried out as follows.

 First, the two portions of metal plate 12 and 13 planes of different metallurgical compositions are placed edge to edge to form the joint plane 14, then said portions of plates 12 and 13 are maintained by conventional clamping members. , such as for example hydraulic or pneumatic cylinders, and the weld bead 15 is continuous and sealed over the entire length of the joint plane 14.

 Then, in the central part of the plate 10 formed by the assembly of the two plate portions 12 and 13, the corrugations 11 are formed, for example by explosion forming.

 Referring now to Figs. 4 to 6, a second embodiment of a plate 10 composing the bundle of plates 1 will be described.

 In this embodiment, the plate 10 is also formed by two portions of metal plate, respectively 22 and 23, of different metallurgical compositions.

 These metal plate portions 22 and 23 are placed edge to edge to form a joint plane 14 and are interconnected by a continuous and sealed weld bead 15 extending over the entire length of said joint plane.

 In this embodiment, the metal plate portions 22 and 23 comprise at the joint plane 14 an edge with a smooth surface, respectively 22a and 22b.

 The joint plane 14 extends over the entire width of the plate 10.

 According to a variant, and more particularly in the case of a circulation of cross-current fluids, the joint plane 14 can extend over the entire length of the plate 10.

 The ends of the plate 10 corresponding to the inlet and outlet areas of the fluids are provided with end plates, respectively 30 and 31, provided with reliefs 30a and 31a which make it possible to orient the corresponding fluid in the circuits of the beam of plates 1.

 To ensure the continuity of the corrugations 11 of each portion of metal plate 22 and 23 at the joint plane 14, an insert 25 is fixed at the level of this joint plane 14 and on the corresponding face of the plate 10 which comprises the corrugations 11.

 As shown more particularly in FIG.

6, this insert 25 has corrugations 26 which are arranged in the extension of the corrugations 11 of the plate portions 22 and 23 to form continuous passages for the corresponding fluid.

 This insert 25 is fixed to the plate 10 by any suitable method.

 According to a first embodiment, the manufacture of the plate 10 shown in Figures 4 and 5 is carried out as follows.

 First of all, the corrugations 11 are formed, for example by explosion, in the central part of the first portion of flat metal plates 22, by making edges on the edges of this portion of plate 22 with smooth surfaces, and forming, for example by explosion, in the central part of the second portion of flat metal plate 23 of the corrugations 11 by providing on the edges of this second portion of plate 23 edges with a smooth surface.

 The plate portions 22 and 23 each have a different metallurgical composition.

 Next, the plate portions 22 and 23 are placed edge to edge to form the joint plane 14 and these plate portions 22 and 23 are held in position using conventional clamping means, such as, for example, hydraulic jacks or tires.

 The weld bead 15 is produced over the entire length of this joint plane 14 and at least one insert 25 is fixed at this joint plane by placing the corrugations 26 of said insert 25 in the extension of the corrugations 11 of the plate portions 22 and 23 to form continuous passages.

 According to another embodiment, the manufacture of the plate 10 formed from the plate portions 22 and 23 is carried out as follows.

 First, the two flat metal plate portions 22 and 23 of different metallurgical compositions are placed edge to edge to form the joint plane 14, then the plate portions 22 and 23 are held in position using means conventional clamping devices, such as hydraulic or pneumatic cylinders, and the weld bead 15 is produced over the entire length of this joint plane 14.

 Next, the corrugations 11 are formed, for example by explosion, in the central part of each plate portion 22 and 23 by providing edges with smooth surfaces on the edges of these plate portions 22 and 23.

 After having produced the weld bead 15, at least one insert 25 is fixed at the joint plane 14 and on the face of the plate portions 22 and 23 provided with the corrugations 11, by arranging the corrugations 26 of this insert 25 in the extension of the corrugations 11 of said plate portions 22 and 23 to form continuous passages for the corresponding fluid.

 Generally, the weld bead 15 is of the through type and is produced by means of a high energy density beam or by the TIG process with or without filler metal or by the MIG or MAG process.

 The plate portions 12, 13 and 22, 23 are of different metallurgical compositions and, for example, a plate portion is made of stainless steel whose chromium content is greater than 13% while the other plate portion is made of alloyed or unalloyed steel or nickel alloy.

 The metallurgical composition of the plate portions 11, 12 and 22, 23 is determined as a function of the heat exchange coefficient and / or as a function of the temperature of the fluids and / or of the nature of these fluids circulating in the bundle of plates 1 .

 Thus, the plate 10 may comprise, at the cold part, a portion of plate made of alloyed or unalloyed steel which has good resistance to corrosion and, in the hot part, a portion of plate made of stainless steel which has good mechanical strength.

 In the embodiments previously described, the plate 10 comprises two portions of plates. Depending on the nature of the fluids circulating in the bundle of plates and as a function of the heat exchange coefficient to be obtained, the plate 10 can comprise more than two plate portions.

 In this case, the methods of manufacturing such a plate also apply.

 In Fig. 7, a variant of a heat exchange plate 10 has been shown.

 As for the other embodiments, the plate 10 is formed by two portions of metal plate 12 and 13 of different metallurgical compositions, placed edge to edge to form a joint plane 14 and connected together by a continuous weld bead 15 and waterproof.

 In this embodiment, the inlet and outlet zones for the fluids are formed by the planar ends of the plates 10 between which are inserted independent plates 35 provided with reliefs to ensure the distribution of the fluids in the heat exchange zone .

 These independent plates 35 are fixed to the corresponding plate 10 by means of spacers 36.

 The independent plates 35 have the same metallurgical composition as the plate portions 12 and 13 or a different metallurgical composition.

 For example, the independent plates 35 are made of stainless steel whose chromium content is greater than 13% or of alloyed or unalloyed steel or else of nickel alloy.

 The metallurgical composition of the independent plates 35 is determined as a function of the heat exchange coefficient and / or as a function of the temperature of the fluids and / or of the nature of the fluids.

 The bundle of plates according to the invention makes it possible to be able to carry out a significant heat exchange between a hot fluid and a cold fluid whose temperature variations on this cold fluid can reach 300 to 4000 C.

Claims (19)

 1. Plate of a bundle of heat exchange plates, of the type comprising a central part provided with corrugations (11) and edges with a smooth surface, characterized in that it is formed by at least two portions of metal plate (12, 13; 22, 23) of different metallurgical compositions, placed edge to edge to form at least one joint plane (14) and linked together by a continuous and sealed weld bead (15) extending over the entire length of said joint plane (14).  2. Plate according to claim 1, characterized in that the corrugations (11) of each portion of metal plate (12, 13) extend to the joint plane (14) to form continuous passages.  3. Plate according to claim 1, characterized in that the metal plate portions (22, 23) comprise at said joint plane (14) an edge with a smooth surface (22a, 22b) on which is fixed at least one insert (25) covering said joint plane (14) and comprising corrugations (26) arranged in the extension of the corrugations (11) of said plate portions (22, 23) to form continuous passages.  4. Plate according to any one of claims 1 to 3, characterized in that the joint plane (14) extends over the entire width of said plate (10).  5. Plate according to any one of claims 1 to 3, characterized in that the joint plane (14) extends over the entire length of said plate (10).  6. Plate according to claim 1, characterized in that the weld bead (15) is of the through type and is produced by means of a beam with high energy density.  7. Plate according to claim 1, characterized in that the weld bead (15) is of the through type and is produced by the TIG process with or without filler metal.  8. Plate according to claim 1, characterized in that the weld bead (15) is of the through type and is produced by the MIG or MAG process.  9. Plate according to any one of the preceding claims, characterized in that at least one portion of metal plate (12, 13; 22, 23) is made of stainless steel whose chromium content is greater than 13%.  10. Plate according to any one of claims 1 to 8, characterized in that at least a portion of plate (12, 13; 22, 23) is made of alloyed or unalloyed steel.  11. Plate according to any one of claims 1 to 8, characterized in that at least a portion of metal plate (12, 13; 22, 23) is made of nickel alloy.  - And to form in the central part of the plate (10) corrugations (11).  to produce over the entire length of said joint plane (14) a continuous and sealed weld bead (15),  - placing edge to edge at least two flat metal plate portions (12, 13; 22, 23) of different metallurgical compositions to form at least one joint plane (14),  12. Process for manufacturing a plate (10) of a bundle of heat exchange plates (1) according to any one of claims 1 to 11, characterized in that it consists  13. A method of manufacturing a plate (10) of bundle of plates (1) heat exchange according to any one of claims 1 to 11, characterized in that it consists  - to form in the central part of at least a first portion of flat metal plate (12; 22) corrugations (11) by providing on the edges of this first portion of plate edges with a smooth surface,  - To form in the central part of at least a second portion of flat metal plate (13; 23) corrugations (11) by providing on the edges of this second portion of plate edges with smooth surface, said second portion of plate (13; 23) having a metallurgical composition different from said first portion of plate (12 22),  placing said portions of metal plate (12, 13 22, 23) side by side to form at least one joint plane (14),  - to produce over the entire length of said joint plane (14) at least one weld bead (15) continuous and sealed,  - And to fix at said joint plane (14) at least one insert (25) comprising corrugations (26) arranged in the extension of the corrugations (11) of said plate portions (12, 13; 22, 23) to form continuous passages.  14. A method of manufacturing a plate (10) of a bundle of heat exchange plates (1) according to any one of claims 1 to 11, characterized in that it consists  - placing edge to edge at least two flat metal plate portions (12, 13; 22, 23) of different metallurgical compositions to form at least one joint plane (14),  to produce over the entire length of said joint plane (14) a continuous and sealed weld bead (15),  - forming in the central part of each plate portion (12, 13; 22, 23) undulations by providing on the edges of said plate portions edges with a smooth surface,  - And to be fixed at said joint plane (14 at least one insert (25) comprising corrugations (26) arranged in the extension of the corrugations (11) of said plate portions (12, 13; 22, 23) to form continuous passages.  15. Bundle of heat exchange plates formed by a stack of plates (10) each comprising a central part provided with corrugations (11) and edges with a smooth face and delimiting between them at least two circulation circuits of at least at least two independent fluids, said plates (10) comprising, on the one hand, a heat exchange zone between the fluids and, on the other hand, at their free ends, an inlet and outlet area for said fluids, characterized in that it comprises at least one plate (10) according to any one of claims 1 to 11.  16. Plate bundle according to claim 15, characterized in that the fluid inlet and outlet zones are formed by the planar ends of the plates (10) between which are inserted independent plates (35) provided with reliefs for ensuring the distribution of fluids in the heat exchange zone.  17. Plate bundle according to claim 16, characterized in that the independent plates (35) are made of stainless steel, the chromium content of which is greater than 13%.  18. Plate bundle according to claim 16, characterized in that the independent plates (35) are made of alloyed or non-alloyed steel.  19. Plate bundle according to claim 16, characterized in that the independent plates (35) are made of nickel alloy.