JP3190675B2 - Plate heat exchanger and method of assembling the same - Google Patents

Abstract

The invention concerns the production of a plate-type heat exchanger in which a bundle (1) of heat exchange plates, between which two fluids circulate, consists of a stack of pairs (2) of plates (3, 3') provided with corrugations and welded together at their lateral edges (5, 5'). Closed conduits (6) are formed for a first heat exchange fluid, said conduits extending longitudinally from one end of the bundle (1) to the other, while gaps between two pairs (2) of adjacent plates (3, 3') contacting each other by means of the outer ridges (7) of the corrugations form open conduits (8) for a second heat exchange fluid.

Description

The present invention relates to a structure of a plate heat exchanger and a method for assembling the same. Generally speaking, a plate heat exchanger is one in which the fluid undergoing heat exchange on each side of a corrugated plate arranged in a parallel relationship so as to be supported by the top of each corrugated body in the longitudinal direction. It differs from a tube heat exchanger by flowing.

For example, as disclosed in French Patent No. 2,471,569 or French Patent Application No. Having a stack of parallel flat plates. The heat exchange plates may be used from one end to the other end of the heat exchanger as they are used to contact each other and create disturbed movements that favor heat transfer across the plates between the fluids. To provide a fluid flow in the longitudinal direction (usually in countercurrent flow to each other). At the longitudinal edges of these plates,
The plates are welded together by a strip or frame that forms a spacer member that maintains the spacing between two successive juxtaposed plates. The stack of plates is surrounded by two metal sheets of relatively sufficient thickness to transfer the weight of the stack to the support.

As is known in the art, the strips are arranged continuously along the entire length of the flat side edge of the plate. The thickness of the strip is commensurate with the thickness of the corrugations which are opposed to each other while the thin metal sheets constituting the plate form a passage for the flow of heat exchange fluid between two successive plates.

It is particularly difficult to actually apply such a structure of the laminate. Furthermore, this results in stresses and crack formation as a result of the difference in thermal inertia between the strip and the thin metal sheet, since the welding operation is performed at substantially different thicknesses of the material to be welded.

The present invention is firstly directed to a laminate structure which is easy to assemble, has a light weight, and solves the above-mentioned problems. The invention is situated in a traditional technical context in which the laminate is arranged inside an enclosure provided to receive and contain the highest pressure fluid.

The invention comprises, according to a main feature, a laminate of a pair of plates comprising a corrugated body and joined together in pairs by welding of the side edges, from one end of the laminate to the other. Forming a closed fluid passage for the first heat exchange fluid longitudinally to the portion, the space between two pairs of adjacent plates in contact by the outer top of the corrugations of the plates alternately forming the second heat exchange fluid. The second fluid is distinguished by being arranged to form an open fluid passageway for the exchange fluid, the second fluid being selectively received to fill the outer enclosure containing the laminate.

The present invention makes it possible to omit the strips in the middle between the side edge plates, not only resulting in a considerable weight reduction of the laminate as a whole, but also above all as a result of the differences in thermal inertia as a result of the stress and stress. This makes it possible to avoid the inevitable consequences of welding operations performed at substantially different thicknesses of the material to be welded between the strip and the thin plate, which lead to crack formation.

According to the invention, a step is taken in which only one of the two passages is closed in a sealed manner. In fact, the first
The welding step consists in welding the side edges of the plates pressed together against each other in pairs, preferably without filling. Thus, each plate pair forms a passage for longitudinal fluid flow from one end of the stack to the other.

The present invention is also directed to a plate heat exchanger structure having a pressure resistant outer enclosure in which a stack of heat exchange plates is disposed. The heat exchanger according to the invention allows the heat exchange fluid to flow between the outside of the enclosure and the end of the stack at the stage of the interposer strip, which connects the plates together and forms an inlet and an outlet for the fluid. Advantageously, means are provided for the discharge.

As will become apparent, the aforementioned inlet and outlet means are preferably arranged such that the second fluid flowing in the open fluid passage fills the outer enclosure. This second fluid is preferably a high-pressure fluid in order to avoid the need to provide a pressure-passing element to the stack. The resistance of the stack is ensured by the high pressure fluid filling the enclosure, preferably against the flow of pressure drop that the fluid undergoes as it passes through the stack.

The structure described here does not require any work involving the welding along the side edges of the entire laminate. Further, in another embodiment, the structure also allows for the construction of a stack of plates from pairs of plates having different widths to ensure greater volume filling of the enclosure (typically a cylindrical shell). Make it possible. Thus, for a given volume, a better heat exchange capacity of the heat exchanger is obtained.

The laminate is advantageously open at both longitudinal ends, on the one hand, for the purpose of facilitating the assembly of the heat exchanger and, on the other hand, for guiding the second fluid longitudinally in the laminate. It is surrounded by a substantially parallelepiped-shaped casing.

According to the invention, the casing has a particularly simple structure, since it is not required to ensure the transmission of pressure. Advantageously, the high-pressure second fluid flowing in the open passage and in the volume of the enclosure obviates the need to use elements for transmitting those pressures.

In another embodiment of the invention, the casing is replaced by two plates consisting of lateral side plates having the same length as the plates and having a width slightly greater than the height of the laminate. These side plates have the function of guiding the second fluid into the open passages of the stack and the function of holding the stack prior to its connection with the inlet and outlet means. Positioning of the laminate inside the enclosure can be achieved by means of attaching the side plates to one another at the side edges of the side plates, such as tie rods or other suitable means.

In another embodiment, which obviates the need to hold the laminate prior to coupling with the inflow and outflow means, a variable width, for example, which occupies a larger volume in a cross-section within a cylindrical enclosure As in the case of the stack of the above, the stack is disposed directly in the enclosure and is only held under pressure by the high-pressure second fluid.

To enable the formation of a fluid flow in the stack from both ends, the stack is advantageously laterally occluded, so as to define a passage for fluid access at the inlet and outlet of the stack. Fluid passages leading to the central portion at the ends, whereas the open passage for the second fluid between the two juxtaposed and laterally welded plate pairs has the same central position. An interposed strip is provided at the longitudinal end of the stack which is arranged in such a way as to ensure that it is closed by the strip in the region.
Conversely, in the two side regions on each side of the central region, the passage for the first (2) fluid is left open while the interposition is made to close the fluid passage. Strips are provided. In this case, the strip used to close each fluid passage closed in the side region is connected to the side edge of the plate so that it can be easily welded to the leak-proof welding connection of the corresponding passage. Often it is beneficial to ensure that it is inclined at the opposite end.

When looking at the ends of the laminate, one can therefore see the central strip and the two side strips in alternating order laterally to the laminate. However, it can advantageously be adapted to overlap from one passage to the other along the edge of the central region. As will be described later, the inner header, which constitutes the means for inflow and outflow of the first fluid, is welded to the strip in the region of the overlap by means of a connection.

It should be noted that welding at this stage does not present any of the problems encountered in the prior art with side strips. In practice, a strip having a relatively sufficient thickness advantageously has a sufficiently short length along the thin sheet to be welded. In addition, the welding operation involves header walls that are also relatively thick compared to the thin sheets that make up the plate.

The means for allowing the first fluid to flow in and out between the exterior of the enclosure and the end of the laminate, according to the invention, advantageously comprise, at each longitudinal end of the laminate, a side strip and a center. An inner connection which is welded by a longitudinal edge to the area of the overlapping portion of the strip and which is welded by a lateral edge to the outer plate of the laminate; and the inner connection and its inner connection And an inner duct which provides a connection to the outside of the enclosure across which the mouth crosses.

The means for draining the second heat exchange fluid advantageously comprises an outer connection port welded along the edge to the end of the casing, and an inner header comprising means for flowing the first fluid. It comprises an outer header path coaxial with the inner duct and comprising an outer duct connecting between the outer connection opening and the outside of the enclosure.

The connection port is preferably provided in a semi-cylindrical shape,
The connection port for the inflow of the second fluid is disposed inside the connection port for the discharge of the second fluid.

The means for injecting the second fluid are similar in structure to the means for discharging the second fluid, but are advantageously high while simultaneously filling the enclosure provided to provide resistance to high pressures. It consists of a simple orifice in the enclosure so that the second fluid at pressure can freely and freely penetrate into the stack.

The present invention also relates to a method of assembling a plate heat exchanger comprising:

In a first welding step, welding the side edges of the plates pressed together against each other in pairs, preferably without filling;-connecting the pairs of plates thus formed with each outer corrugated body. The stack of plates is preferably held in a parallelepiped casing open at both ends, with the plates stacked in contact and in contact with each other; Interposing strips at said ends defining passages for welding, in a second welding step, welding the strip ends and the lateral edges of the plate, while simultaneously overlapping the inner connection openings with the strips Welding to the area; in a third welding step, welding one or more outer connection ports to the end of the casing surrounding the laminate.

The following is a description of the individual embodiments, which serve to gain a better understanding of the essential features and advantages of the present invention, but which are not to be construed as limiting, but which do not include any limitations. This will be described in more detail with reference to the accompanying drawings.

FIG. 1 is a cross-sectional view of a plate stack of a plate-type heat exchanger according to the present invention in a region where the plate has a corrugated body.

FIG. 2 is a cross-sectional view of the plate-type heat exchanger according to the present invention in the vicinity of one longitudinal end of the plate stack.

FIG. 3 is a partially exploded perspective view of the plate heat exchanger according to the present invention.

FIG. 4 is a cross-sectional view schematically showing another embodiment of the plate heat exchanger according to the present invention.

FIG. 5 is a partial schematic perspective view of a plate heat exchanger according to the present invention.

In all of the drawings, the scale is not corresponded for clarity and the drawings are schematic. Also,
For the sake of clarity, the same components are denoted by the same reference numerals in different drawings.

As shown in FIGS. 1 and 2, the heat exchanger plate laminate 1 according to the invention is composed of a pair 2 of plates 3, 3 '. Each pair 2 of these plates 3, 3 'is formed by stacking two thin metal sheets constituting the plates 3, 3', and these plates 3, 3 ' They are opposed to each other by an inner top 4 of the corrugated body. These corrugations constitute a means for forming a flow of heat exchange fluid flowing between two adjacent plates 3, 3 'forming the same pair. Furthermore, the plates 3, 3 'have a frame with a smooth surface without corrugations. The two plates 3, 3 'forming a pair 2 by this frame are in particular welded to one another along the side edges 5, 5' of the plates 3, 3 'pressed together without any additional filling. obtain.

The pair 2 of the plates 3, 3 'thus formed is:
A closed passage 6 is formed for the longitudinal flow of the first heat exchange fluid from one end to the other end of the laminate 1.

The pairs 2 of these plates 3,3 'are then stacked one on top of the other to form the outer top 7 of the corrugations of the plates 3,3'.
Thus, the space between two pairs of adjacent plates in contact forms an open passage 8 through which the second heat exchange fluid flows.

In the example described, the laminate 1 is then held in a simple parallelepiped-shaped casing 9 opening at both ends. This casing 9 is intended, on the one hand, to guide the second heat exchange fluid in the open passage 8 and, on the other hand, in an enclosure 10 (FIG. 5) provided to withstand the fluid pressure as a secondary function. The laminate 1 is intended to be held in a predetermined position until the laminate 1 is placed under the pressure described below.

In the heat exchanger, the fluid flowing in the closed passage 6 is preferably a low-pressure fluid or a fluid that does not fill at least the enclosure (usually a cylindrical shell) containing the stack 1 of plates 3,3 '. It is. Indeed, since the high pressure fluid thus flows through the open passage 8 while simultaneously filling the enclosure 10, as will be seen later, the casing 9 therefore does not need to transmit pressure.

As shown in FIG. 2, interposed strips 11, 12 are provided at predetermined positions at both ends of the laminate 1 of the heat exchange plates 3, 3 '. These strips 11 and 12 serve to define the fluid passages at the inlet and outlet of the laminate 1, in other words, at the connection points of the fluid passages 6 and 8 to the connection ports (connecting boxes) 13 and 14 (FIG. 3). Next, the welding of the ends of the strips 11, 12 and the lateral edges 15, 15 'of the smooth surface of the plates 3, 3' is performed on the inner connections 13, 16 (FIG. 5) for the first fluid. As welding, it can be done simultaneously.

In this heat exchanger, the low pressure first heat exchange fluid flows at the upper end of the heat exchanger in the inner header 18 (collecting the high pressure second heat exchange fluid) as shown in FIG. In turn, the entire stack 1 is suspended from the cylindrical shell 10 by an inner header 18 (outer header 17) that collects this low pressure first heat exchange fluid. At the bottom of the heat exchanger, the high pressure second fluid is simultaneously filled with the shell 10 provided to withstand high pressure and the low pressure first fluid flows out of the laminate 1 through the inner header 19. Is the laminate 1
Enter freely within.

These headers 17, 18, and 19 are stacked from the outside of the enclosure 10 to the laminate 1
Means for inflow and discharge of the heat exchange fluid toward the end of the heat exchanger.

Each of the inner header paths 18 and 19 is constituted by inner connection ports 13 and 16 having a generally semi-cylindrical shape, and inner ducts 20 and 21 connecting between the inner connection ports 13 and 16 and the outside of the enclosure 10. Have been.

The outer header path 17 is composed of an outer connection port 14 having a generally semi-cylindrical shape, and an outer duct 22 connecting the outer connection port 14 and the outside of the enclosure 10 to each other. Duct 22 is coaxial.

During the step of welding the plate 3 onto the plate 3 ', the laterally closed passage 6 is open at the end of the central region 23 and both the top and the bottom of the laminate 1 Two side regions 24,2 on each side of the central region 23
At 5, it is closed by a strip 11. Two juxtaposed pairs 2 of plates 3,3 'welded on the sides
The open passage 8 formed for the second fluid therebetween is closed by the strip 12 in the central region 23 to ensure that the passage 8 does not communicate with the inner headers 18, 19 on the contrary. I have. The two side regions 24, 25 are provided with strips 11 which close the first fluid passage 6, and the second fluid passage 8 is provided at its upper end with an outer header 17 or similar guiding means. It remains open so as to communicate with the inner space of the lowermost enclosure 10 of the laminate 1.

When strips 11 and 12 are arranged in place,
These strips 11 and 12 are correspondingly two
In the area of the overlap 30 of the strips 11, 12 to the edges and in the central area 23 of the lateral edges of the two outer plates of the laminate 1, the inner connecting ports 13, 16 are welded to the plates 3, Welded to 3 'lateral edge at the same time.

Eventually, the last welding step is constituted by welding the outer connection port 17 to the end of the casing 9 surrounding the laminate 1.

The other embodiment shown in FIG. 4 shows the best volume filling obtainable by the present invention in a cylindrical shell 26 constituting the outer enclosure of the heat exchanger. In this case, it is configured as a laminate 27 composed of plates 28 having different widths. As shown in this figure, the stepped cross-section of the stack 27 is such that the fluid passages for the second fluid between the plates 28 can remain open so that the juxtaposed pairs of plates 28 can remain open. This is made possible by forming the laminate 27 in a shape.

However, it will be understood that the present invention is, of course, not limited in any way to the preferred embodiment given above by way of example. On the contrary, it is clear that the invention extends to many other alternative embodiments. In particular, adding along the length of the pair of plates to be welded a side spacer member disposed between two adjacent pairs but not welded to reduce possible vibrations at this location. Can be useful.

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Claims (13)

(57) [Claims] 1. A plate heat exchanger having a heat exchange laminate comprising corrugated plates supported on each other by the tops of each corrugated body, wherein said plates (3,3 ') comprise: 3 ') the sides of the plates (3,3') in the longitudinal direction from the upper end to the lower end of the laminate (1) so as to form a fluid passage for the first and second heat exchange fluid between them. Welded in pairs at the edges, the passages are each alternately closed (6) and open (8) in an outer enclosure (10) containing the laminate (1), and the plate ( 3,3 ') are also interposed strips (11,1') forming the inlet and outlet of the fluid.
Coupled to the end of the stack (1) by 2), wherein the heat exchanger comprises an inner duct (20) for guiding the fluid through the closed fluid passage (6) and the outer enclosure (10). And at least one connection port welded to said interposer strip (11, 12) at the upper end of said laminate (1) to guide the flow of said first heat exchange fluid between A plate-type heat exchanger. 2. Each of said closing fluid passages (6) is provided with two intermediate members for stopping flow at each end on each side of a central region (23) constituting an access port to said closing fluid passage (6). Inserting strips (11) are provided at the two longitudinal ends of the closed fluid passage (6) and each of said open fluid passages (8).
Connects the intervening strip (12), which stops the flow at each end of said central region (23), to the longitudinal direction of its open fluid passage (8).
The plate type heat exchanger according to claim 1, wherein the plate type heat exchanger is provided at each end. 3. The length of said interposed strips (11, 12) is
When the interposed strips (11, 12) are provided at predetermined positions, they have a length that has an overlapping area from one passage to the other at the edge of the central area (23). The plate heat exchanger according to claim 2. 4. The side edges (5, 5 ') of two adjacent plates forming said pair (2) of said plates (3, 3') are pressed together and welded without filling. The plate heat exchanger according to any one of claims 1 to 3, wherein: 5. A casing (9) open at both ends and surrounding said laminate (1) so as to guide the second heat exchange fluid in said open fluid passage (8) laterally. The plate heat exchanger according to any one of claims 1 to 4, wherein the plate heat exchanger has: 6. The laminate (27) is constituted by a pair of plates (28) having different widths allowing a greater filling of the volume of the outer enclosure (10), said enclosure comprising a cylindrical shell (26). The plate heat exchanger according to any one of claims 1 to 5, characterized in that: 7. A second heat exchange fluid is applied to each side of the laminate (1) facing the side edge of the plate (3, 3 ') from one end of the laminate (1). Two sheets having a length substantially the same as the length of the plate (3, 3 ') and a height substantially the same as the height of the laminate (1) so as to be guided longitudinally to the ends; The plate-type heat exchanger according to claim 4 or 6, further comprising: 8. The connection port (13) for the first heat exchange fluid to flow in the closed fluid passage (6).
Is a semi-cylindrical shape, and the insertion strips (1
The plate heat exchanger according to any of the preceding claims, characterized in that it is welded to the lateral edges of the outer boundary plate (1,12) and of the laminate (1). . 9. The connection port (13) is connected to the inner duct (20).
At the same time, an inner header path (18) for flowing the first heat exchange fluid into the closed fluid path (6) of the laminate (1) is formed, and a similar header path (19) is formed in the enclosure. Plate according to any of the preceding claims, characterized in that a plate is provided at the lower end of the stack (1) for discharging the first heat exchange fluid from (10). Type heat exchanger. 10. The heat exchanger has a semi-cylindrical shape and an opening in the casing (9) for discharging a second heat exchange fluid to flow through the open fluid passage (8). Outer connection port (14) welded to the end
And an outer header path (17) having an outer duct (22) connecting the outer connection opening (14) and the outside of the enclosure (10). The plate-type heat exchanger according to any one of the above. 11. The inner header passage (18) for the inflow of the first heat exchange fluid is included in the outer header passage (17) for the discharge of the second heat exchange fluid. The plate-type heat exchanger according to claim 10, wherein the outer header path (17) is provided at an upper end of the laminate (1). 12. The means for inflowing said second heat exchange fluid opens into said enclosure (10) via a simple orifice, so that said second heat exchange fluid is simultaneously present in said enclosure (10). The plate heat exchanger according to any one of claims 9 to 11, wherein the heat exchanger freely flows into the laminate (1) while satisfying the following conditions. 13. In a first stage, the side edges (5, 5 ') of the plates (3, 3') pressed together are welded in pairs without the addition of fillings; Stacking pairs (2) of plates (3, 3 ') formed in a superposed relationship, and disposing the stack in a parallelepiped casing (9) open at both ends. At the ends of the channels (6, 8) formed by said laminate, interposed strips (11, 12) provided at both ends of said laminate to form channels for fluids; In the second welding stage, the interposed strip (11,1
2) welding the lateral edges (15, 15 ') of the plate and welding the inner connection ports (13, 16) to the overlapping area of the interposing strips (11, 12); 3. The welding step of claim 3, wherein at least one outer connection port (14) is welded to one end of a casing (9) surrounding the laminate (1). 13. The method for assembling the plate-type heat exchanger according to any one of 12.