KR20090048433A - Hollow platelet heat exchangers - Google Patents

Abstract

One of these heat exchangers (76) consists of a stack of thin-metal walled hollow platelets (7S1-J5), 12 cm long and 5 wide. Each of these walls has a central region stiffened by alternating bosses with steep slopes, situated between two connection regions. Each wall is made by pressing then cutting an appropriate sheet of metal (aluminium 0.3 mm thick). The edges of the two fin walls form steps, symmetrically welded, the height of each step determining the internal half-thickness of a fin. Each platelet connection region ends in a narrow mouth with a cross section that has the same surface area as the embossed central region, and is welded to the edges of a slot made in an external manifold (80-82). The thickness of the internal channel of a platelet is about 0.4 mm when the fluid concerned is a liquid (water) and that of the spaces between the platelets is 7 mm when the other fluid is a gas (air). By hot pressing or thermoforming, sheets of glass or polymer may also be used but the performance is not as good. A radiator can be made of several exchangers mounted in parallel on each side of two flat main manifolds. Applications: any heat exchangers with high volumetric conduction, low weight and low pumping and ventilating power.

Description

Hollow Platelet Heat Exchangers

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high performance heat exchanger constructed by stacking hollow plates, which has a low front surface area and high volume conductivity, and requires less power to flow the fluid, thereby making the liquid and / or gas relatively high pressure difference and temperature difference. It relates to a heat exchanger which can be handled under.

The present invention further relates to a heat exchanger, which is similar in general to the foregoing but with lower performance and more suitable for a particular application.

Hollow plate heat exchangers exhibit much higher performance when applied to radiators in heat engines than solid fin heat exchangers. Indeed, in such liquid / gas heat exchangers, the spacing between adjacent hollow plates is much greater than the spacing between solid fins, with the same bulk conductance, and as a result, the hollow plate heat exchanger has a heavier weight than solid fin heat exchangers. , Volume, front surface area and power consumption (pumping of liquid and / or blowing of gas) are significantly smaller. Nevertheless, solid metal fin heat exchangers are still widely used in various fields. This is the case, however, where conventional radiators are applied to heat engines, the front surface area (main cress section) of these radiators amounts to about 0.3 dm ² per kW of heat dissipated and the mechanical power consumed to operate them. Silver accounts for up to 10% of the thermal energy released and is consumed more when the temperature difference is low, which is a clear indication of the advantages of the hollow plate heat exchanger.

A heat exchanger formed from a one-piece stack hollow plate of polymer, glass or metal is described in EP 1 579 163 B1, owned by TET. One of the methods of manufacturing these heat exchangers has an embossed wall in which deep alternating bosses are formed by a process of thermoblowing a polymer parison. Producing a blank in accordion form with biconvex bellows and compressing the blank under control. The compression process results in the bellows having the final form of a single layer rigid hollow plate with narrow inner channels connected to two inner manifolds. Such single layer polymer heat exchangers have a range of required volume conductivity (20 W / ° C dm ³ or less), and when the pressure difference of the fluid being handled is in a suitable range (up to 0.1 MPa) and is not high temperature (100 ° C.) Very satisfactory results in the application case. In many practical applications, the advantages in weight, cost, volume and power consumption (3 to 5% of the discharge power) are sufficient to compensate for the drawbacks of the above constraints, in particular the initial temperature difference between the heat exchanged fluids Relatively small (<60 ° C) results in particularly satisfactory results.

Single layer heat exchangers composed of hollow plates of the embossed polymer wall have many advantages. The wall allows the combination of stiffness and thickness, which are mutually opposite properties, to reduce weight, cost and volume. In addition, despite the laminar flow of the cooling fluid, the thermal conductivity between the fluid and the hollow plate is excellent by the narrow inner channel. On the other hand, relatively strong turbulence is generated in the air flow between the plates by the embossed wall, so that the distance between the plates can be increased, and as a result, the energy required to push the air between the plates can be significantly reduced. Will be. Moreover, the overall thermal conductance of the heat exchanger is increased as the apparent thermal conductivity of the air is increased due to the turbulence between the plates.

However, experience has shown that the technique, which consists of two stages of the thermal blowing and the controlled compression process of the biconvex bellows polymer blank, is thereby intended to increase the desired performance level of the manufactured heat exchanger, or in particular to improve the volumetric thermal conductivity. In this case, only limited results were obtained. Although the thickness of the inner channel or plate wall is an important parameter in determining the volume conductivity of the heat exchanger, it is impossible to fully control the two-step manufacturing process with respect to the thickness in the manufacturing process of the single layer hollow plate. In practice, the average thickness of the inner channel of the hollow plate is 2 mm on average with a dispersion value of at least 30%, and the average thickness of the wall reaches 1 mm with a dispersion value of about 50%. These dispersion values are mainly generated by the nonuniform shrinkage of the wall during the thermal blowing process for the blanks.

Not only is performance limited due to thickness issues as described above, but the presence of an internal manifold for layered hollow plates is also another performance limiting factor. That is, since a central channel common to all hollow plates is formed, the liquid flows directly and rapidly between the two manifolds, thereby making little contribution to the heat exchange required by the relatively wide central channel.

On the other hand, a high performance cooling device for various applications is described in International Patent Application WO 2006/010882 to TET. The radiator of these devices corresponds to a heat exchanger manufactured according to the method of the above-mentioned European patent of TET. According to the contents of the application, for a particular use (cooling for the recirculation of diesel engine exhaust), a single piece with a hollow metal plate capable of withstanding even greater pressure and temperature differences than a one-piece polymer heat exchanger A heat exchanger is provided. For this purpose, metal accordion type blanks are produced by a hydroforming method. Hydroforming is a well known technique and may be effectively applied to the production of single-piece heat exchangers with metal hollow plates, but at present it is difficult to do this accurately, and furthermore has its own limitations in terms of theoretical efficiency. Indeed, as the heat resistance of a cooling liquid such as water or oil increases, the heat resistance of the liquid layer laminarly flowing inside the hollow plate to an average thickness of at least 2 mm also inevitably increases, which is expected to be provided by the metal wall. Many of the intended benefits of low thermal resistance cancel out.

Thus, there has been a need to develop other methods for producing metal heat exchangers with very high performance that are suitable for a variety of specific applications. To meet this goal, the new metal heat exchanger must have low weight, volume, front surface area and power consumption to match the single piece heat exchanger mentioned above. At the same time, it must be possible to operate properly at much higher volume conductivity (eg at least 100 W / ° C. dm ³ ) and at pressures and temperatures of, for example, 100 Mpa and 600 ° C. Additionally, in connection with certain applications, such as using corrosive fluids, low performance polymer, glass heat exchangers can be obtained from the metal heat exchanger.

Unlike the one-piece metal heat exchanger, which is designed for application to exhaust gas cooling of diesel engines, new heat exchangers, especially heat exchangers suitable for this intention, have as narrow and accurate internal channels as possible, have rigid and thin walls. Hollow metal plates shall be provided. The overall characteristics of such a heat exchanger have completely different characteristics from those of previous heat exchangers. These properties are developed for the cooling of transformers in power distribution systems and can be introduced from the heat exchanger devices described in US Pat. Nos. 3,315,447 (1964) and 3,853,851 (1974). The device consists of a large hollow metal plate welded to two outer manifolds with embossed walls, which can be arranged vertically and cooled by air circulating in natural convection.

The first object of the present invention is to form a hollow plate having a thin metal wall reinforced with strength by embossing, and can be manufactured easily and reliably, with low weight, volume, surface area and power consumption and high volume conductivity. And a high performance heat exchanger that can be applied to fluids in liquid and gaseous state.

A second object of the present invention relates to an improved heat exchanger, which is similar in performance to the above heat exchanger but which is inferior in performance but is particularly suitable for a given particular application, comprising a hollow plate layer having a thin polymer or glass wall reinforced by appropriate embossing. It relates to a heat exchanger provided.

A third object of the present invention relates to a compact radiator with a small front surface area, which can be produced using the improved heat exchanger, and to a radiator having a high thermal conductivity and very low pumping and ventilation power.

The heat exchanger according to the present invention is a heat exchanger having a small weight and volume, high volume conductivity, and applied to a fluid having a high pressure difference and a temperature difference,

-Hollow metal plates with narrow internal channels are arranged in layers at regular intervals and connected to the outer manifold;

The plate has an embossed central zone, the central part being located between two connecting zones having a narrow opening of an area corresponding to the cross-sectional area of the central part;

The walls of the plates are formed by stamping and cutting metal sheets;

In a heat exchanger, in which the side edges of the two walls forming the hollow plate are welded;

The wall of each hollow plate is formed of a thin plate with rigidity and the embossing center has one or more sets consisting of alternating aligned bosses, the alternating bosses having a hard warp strain hardening; Having a plurality of sharp strain hardened faces, and forming a plurality of sharp edges which are inclined and / or perpendicular to the alignment line of the boss;

The spacing between the opposing faces is uniform and small and substantially constant with respect to the pressure difference applied;

-A narrow gap between the plates; is characterized in that the heat exchanger.

Before describing the advantages of the present invention, note that in the US patent in question, the wall of the plate does not need to be thin, and therefore the rigidity of the plate is not particularly problematic, so that embossing at the center of the wall is not a solution to the rigidity problem. Should be. The rigidity problem can be solved without difficulty as long as the wall is of sufficient thickness made of a conventional metal material, and the embossing in the present invention is simply to increase the heat exchange area without increasing the dimensions of the heat exchange plate. If this is the case, it can be achieved by longitudinal undulation formed by relatively small recesses arranged evenly of the wall. The patent discloses a specific profile of such reliefs, the characteristic shape of which is not a concern for this type of heat exchanger, so the disclosed reliefs can be found in their original form as original features. none. However, the undulation causes undulations in the thickness of the inner channel of the hollow plate, changing symmetrically around a relatively high average value. Moreover, the walls of the inner channel are not provided with opposite slopes.

According to the first aspect of the present invention, firstly, the present invention includes a plate having a very thin rigid wall (for example, a steel plate of 0.15 mm), which has a high hardness and elastic limit due to strain hardening. Which is obtained incidentally by a conventional (cold) stamping process, in which the faces of each of the hollows and protruding bosses act as rigid strips and furthermore the pointed ends are beams into which these strips are fitted. Act as. The rigid strip is only deformed in a very limited range even when the differential pressure is applied. In particular, even when overpressure is applied from the outside, the amount of deformation is always maintained in a range far less than half of the inside thickness of the hollow plate, and the inside thickness of the hollow plate can be accurately determined by the design value at intervals between the boss inner surfaces. It is formed very small in value (for example 0.3 mm). This prevents the opposing surfaces of the heat exchanger from contacting each other, so that the function of the heat exchanger between the two fluids can always be performed accurately.

In each of the embossed hollow plates according to the present invention, the metal constituting these walls is deformed and hardened, and the moment of inertia is significantly increased by the alternating boss, so that the rigidity of itself is significantly increased. This very thin strip of double complementary stiffness allows it to work perfectly as an efficient heat exchanger even when the pressure difference between the two fluids circulating along their two surfaces is large. The direct feature of the stamping alternating boss, stiffening, forms the basis of the present invention. The alternating boss takes the form of a steeply deformed hardened surface, which is caused by local tensioning of the sheet with an initial flat surface, resulting in the formation of a number of thin, tough strips, all ends of the strip Is integrally coupled to the beam formed by the pointed end of the boss.

The pointed ends with dihedrons formed between the slopes have another effect of improving the apparent thermal conductivity of the air. The corner portion disposed in the inclined or perpendicular direction to the flow direction of the air exhibits the effect of generating a considerable amount of turbulence in the air flow passing through the narrow gap between the plates at high speed. This configuration is of little significance in the case of heat exchangers in which the relief plates are arranged vertically, as in the aforementioned US patent, and in which air flows at a slow rate by natural convection through unspecified spacing between the plates. will be.

In the following, with reference to the above-mentioned European patent, it can be seen that all of the performance constraints of the aforementioned patent can be solved by the present invention, if the present description concludes. Walls and internal channels can be formed to be very thin and precise, with the thickness of the required design dimensions, and as will be described below, the central channel can be removed. Conversely, all of the positive features associated with the embossed wall of the hollow plate of the one-piece polymer heat exchanger described in the European patent are retained. These features are complemented by the properties resulting from strain hardening of the metal sheet. In addition to the use of very thin walls and the formation of particularly narrow internal channels (which are not well known in the prior art with regard to the high pressure differences to be applied), the combination of the above-mentioned advantages and the advantages of the heat exchanger described in the US patent As a result, new, non-obvious heat exchangers could be developed. As a result, the new heat exchanger according to the present invention has a performance level that goes beyond the high efficiency of the single piece polymer heat exchanger according to Titi owned European patent.

According to a feature of the invention that supplements the above main features,

Each hollow plate has at least two rows of alternating bosses;

Two adjacent rows of alternating bosses are separated by narrow flat sections 36 formed of two internal protrusions which are welded by stamping or thermoforming;

The height of the protrusion corresponds to half the maximum internal thickness of the hollow plate.

Such a configuration aims at improving the rigidity of a plate having a large dimension (m ² ) in the US patent in question, but the heat exchanger according to the present invention provides the following two special advantages. First, when a relatively high internal overpressure is applied to the hollow plate, the inner thickness of the embossed center portion remains constant due to the straight inner compartment, regardless of the pressure difference across the thin plate. As a result, a hollow plate with a very thin wall reinforced by proper embossing can be tolerated without damage even with relatively high internal overpressure. Without welded inner projections, adjacent rows of highly rigid alternating bosses are separated by a flexible zone that hinges therebetween, and when overpressure is applied, the plates swell lightly, thereby The gap between them is significantly reduced or, in severe cases, the plate is suddenly damaged. However, according to the present invention, by having two welded inner protrusions, it is not necessary to form the thickness of the hollow plate as a whole to be able to withstand instantaneous internal overpressure. This means that a lighter, cheaper heat exchanger can be produced.

The second advantage of the weld projection is shown in terms of heat exchanger efficiency. Internal compartments formed between adjacent rows of alternating bosses as described above constitute a barrier to liquid flow entering the hollow plate. The first effect of each barrier is to prevent a significant amount of fluid from flowing directly between the two outer manifolds along a flat wall with a narrow surface area, thereby preventing the required heat transfer efficiency. Another effect of the barrier is to direct the incoming flow to two rows of alternating bosses with good heat exchange efficiency, thereby maximizing the performance of the heat exchanger.

It should be noted that the two advantages are not of great concern in heat exchangers formed of large hollow plates with relatively thick walls as described in the US patent. In such a heat exchanger, the maximum pressure difference occurring in each part of the large vertical plate is a relatively low static overpressure caused by the cooling oil. The heat exchanger according to the invention can be installed anywhere in a suitable position, and in particular operates under extremely high differential pressures, and is thus almost independent of the problem of static overpressure.

According to another feature of the invention that supplements the aforementioned features,

The angle formed by the vertical lines of the adjacent faces of the alternating bosses is at least 30 °, so that turbulence can be effectively generated by the pointed ends between the faces and withstand the pressure difference between the fluids;

The maximum angle formed by the vertical lines of the adjacent surfaces of the alternating bosses is limited to a limit depending on the material to be stamped or thermoformed.

According to another feature of the invention which supplements the above-mentioned features, the opposing face of the hollow plate has parallel walls, and the intervals for separating the walls are constantly formed in an order equal to the thickness of the walls.

According to another feature of the invention that supplements the aforementioned features,

Said alternating bosses have two faces in the form of an isosceles trapezium which share one longitudinal side and share two central rhomboid faces;

The length of the long diagonal of the oblong side corresponds to several tens of the thickness of the plate wall.

According to another feature of the invention that supplements the aforementioned features,

Said alternating bosses have two faces in the form of an isosceles triangle, sharing two central hexagonal planes, said two central hexagonal planes sharing transverse edges;

The spacing between the transverse edges of the central hexagonal plane corresponds to several tens of the thickness of the plate wall.

According to another feature of the present invention that supplements the aforementioned features, the embossed central portion of each hollow plate is external through two connections having horizontal ends of gently sloped walls forming truncated cones portions. Coupled to the manifold.

According to another feature of the invention that supplements the above features, the outer manifold of the hollow plate is formed with an aerodynamic profile to minimize drag of the heat exchanger.

According to another feature of the present invention that supplements the above features, a plurality of secondary surfaces are formed on the symmetric boss surface and appear to be cut in diamond form, further comprising a complementary pointed end.

As a result of such various configurations, the heat exchanger produced according to the present invention has a particularly high volume conductivity. There are several reasons for this: (1) Since the plate is provided with metal walls, the thermal resistance can be neglected. (2) Although water or oil forms a laminar flow and exhibits relatively high heat resistance, very thin layers of water or oil inside the plate have extremely low heat resistance. (3) As the height of the boss and the total number of pointed ends increase, turbulence and apparent thermal conductivity of air circulating between the plates increases. Multiple alternating bosses with an inclined plane of about 45 ° are formed in at least two rows, thereby complementing the mutual effect between the various parameters. Stamping of bosses with slopes of 50 ° or less is a standard problem without major problems, and by allowing the angle between the vertical lines of adjacent surfaces to be at least 30 °, not only can turbulence be effectively generated in the air flow, The edges have sufficient rigidity to match the beam, and the ends can be comparable to the beam network as a whole.

Moreover, since the same plate connected to the outer manifold is stacked to form a heat exchanger, the pressure drop of the liquid circulating inside the plate is significantly reduced with a relatively fast steady laminar flow, and the power required to pump the liquid is also remarkably reduced. Is reduced. In addition, an external manifold with an aerodynamic profile is applied, which is installed parallel to the flow direction of the air, thereby significantly reducing the power required for the aerodynamic drag and / or air circulation of the radiator.

With regard to the metals that can be used in the manufacture of the hollow plates according to the invention, the choice is not so large, but is well known to those skilled in the stamping art and ultimately, the choice (for example aluminum or steel). Silver is determined by the mechanical behavior of the metal in the operating temperature range of the heat exchanger to which the plate is applied.

Due to the various characteristics as described above, the high performance heat exchanger according to the present invention can be industrially produced by a series of operations capable of precise control. Accordingly, it is easy to automate, it is possible to reduce the cost of mass production of heat exchanger. The operations required for production are as follows.

1) stamping and cutting out the same plate from the sheet metal sheet;

2) inverting the head and the corners of one wall;

3) assembling two adjacent walls by welding the protrusions of the side flanges and the inner central partition;

4) The process of mounting and fixing the finished hollow plate on two outer manifolds.

According to the present invention, a compact radiator having a volume conductivity,

Two equal groups of thin metal hollow plate heat exchangers, the two groups being coupled to two upstream and downstream manifolds, the manifolds having a flat right angle trapezoidal face, with right angle edges opposite each other Spaced apart from one another so as to;

Each upstream and downstream manifold of each group heat exchanger is respectively coupled to the corresponding face of the main upstream downstream manifold at regular intervals slightly larger than the width of the central part of the heat exchanger.

According to this aspect of the invention, it is possible to have a writer with a very high volume conductivity while minimizing the main cross-sectional area (0.10 dm ² per 1 kW emission energy). In addition, the heat exchanger according to the present invention is formed by stacking a plurality of metal hollow plates, and even a large number of heat exchangers may be easily mounted on two main flat manifolds. In addition, according to the compact radiator, since the power required for pumping and air circulation is extremely small, the same thermal conductivity results in a level of about 1/5 or less of the power required for the solid fin radiator.

1 shows a plan view of a first embossed wall of a hollow plate according to the invention;

2A is a plan view of a second embossed wall of the hollow plate according to the invention, and FIGS. 2B, 2C show a specific side of the wall;

3 is a longitudinal sectional view of an alternating boss of a first wall;

4 is a longitudinal sectional view showing one end of the hollow plate welded to the manifold;

5 shows a perspective view of a heat exchanger with fifteen hollow plates;

6 is a plan view of a radiator constructed by a heat exchanger according to the invention;

Hereinafter, the features and advantages of the present invention in more detail and clearly described by the preferred embodiment of the present invention.

1 shows a first embodiment of a thin metal wall forming a hollow plate. The wall is cut and formed after the stamping operation, and the embossed central portion 13 is disposed between the two connecting portions. In one example, the wall is made of aluminum 0.3 mm thick, the width of the embossed center portion is 60mm, the length is 76mm. The central portion 13 has two rows of alternating bosses 12 and 14 formed equally adjacent to each other, and the two rows of alternating bosses are partitioned by a flat portion 16 having a width of 4 mm. The two connections 18, 20 have smooth walls. Each row is provided with two identical alternating embossing zones of projecting bosses and recesses. For example, in rows 12-14, 22 bosses with _{1-2 1-2} and 24 _1-2 and bosses 22 ' _1-2 and 24' _1-2 are formed, the latter being grayed out.

Each boss 22 _{1-2-24 1-2} or each recess 22 ' _1-2 and 24' _1-2 is formed in the shape of a roof and has four inclined surfaces with four inclined pointed ends. For example, each alternating boss in row 12 may have (1) two symmetric trapezoids (26 _1-2 , 28 _1-2 ) in each of the protruding bosses and two symmetric trapezoids (26 ' _1- ) in each of the recesses. ₂ , 28 ' _1-2 ), the base of each trapezoid is 19 mm in length, and (2) two isosceles triangles (30 _1-2 , 32 _1-2 ) in each of the protruding bosses, respectively It has two isosceles triangles (30 ' _1-2 , 32' _1-2 ), and the length of the base of each triangle is 28mm, and (3) the longitudinal top of the protruding boss (34 _1-2 ) and the concave portion was the length direction has a top portion (34 _'1-2), (4) is formed of the same height of 5mm. Tetrahedron by two pairs of isosceles triangles (30 _1-2 , 32 _1-2 , 30 ' _1-2 , 32' _1-2 ) located in the neighboring bosses of the alternating embossed portion in column 12 (as in column 14) It should be noted that is formed.

In the center of the narrow flat portion 16 which divides the embossed central portion 13 of the wall 10 into two compartments, an internal protrusion 36 is formed with a width of 2 mm, which has a symmetrical surface by a stamping process. It is formed so as to have maximum stiffness as the stamping technique allows. The protrusion 36 is formed at a height corresponding to half of the maximum distance from which the top of the boss is separated from the hollow plate to be manufactured (0.2 mm according to the specific example of the following description). By two lines 38-40, the parallel outer ends of the alternating bosses of two rows 12-14 on the hollow plate are separated from the pair of parallel flanges 42-44 to seal the two plate wall surfaces. Form part of the face. Lines 38-40 and flanges 42-44 have a width of 1 mm and are stepped to a height of 0.2 mm, corresponding to half the thickness of the plate inside the top of the boss. The two lines 38-40 terminate at flat portions 46-48 on the two connections 18-20 of the wall 10, and the two parallel flanges 42-44 are connected to a pair of pairs on the connection. inclined outer flange ending with a bar (50 ₁ -50 _2, 52 ₁ -52 _2), which forms the other sealing surface of the plate wall surface. Each flange 50 _1-2 , 52 _1-2 is formed at an angle of 60 ° to the longitudinal symmetry line of the wall 10. At the end of each connection 18-20 is provided with a substantially flat truncated cone portion, the semi-cone angle being 87.5 °. The tapered portion in this way is bounded by a pair of arcs 58 _1-2 and 60 _1-2 , the latter being 8 mm long. The ends of the connecting portions are joined to each other with a step of 1.5 mm in height, and the cross-sectional area of the upstream and downstream openings of the hollow plate thus formed is 24 mm ² , which is equal to the cross-sectional area of the space inside the embossed central portion 13 of the plate 13. Roughly matches.

2A shows a second embodiment of a thin metal wall 11 formed by cutting after a stamping operation. The wall 11 of the present embodiment differs only from the wall 10 and the embossing center of the above-described embodiment, and this embodiment has a single row of bosses 15, the width of which is 16 mm, in the form of alternating bosses. Is formed. Three protruding bosses 22b _1-3 and three recesses 22'b _1-3 are formed in a line, the latter being shown in gray in the figure. Each drawing boss and the recess are formed in the shape of a roof having four steep slopes. The three alternating bosses in row 15 have (1) side faces that are symmetric triangle pairs (25b _1-2 , 27b _1-2 , 29b _1-2 ) on each of the protruding bosses, and symmetric triangle pairs (25'b) on each of the recesses. _1-2 , 27'b _1-2 , 29'b _1-2 ), and the base of each triangle is 14mm long, and (2) the adjacent boss and the center hexagon (31 _1-5 ) Although shared, the length of the transverse top is 18 mm, and is formed at the same height of 5 mm.

2B and 2C show that various modifications are possible to the boss face of FIGS. 1 and 2A, and that the two main faces of FIG. 2A are provided with secondary faces. FIG. 2B shows a side triangle 25, which forms a relatively flat tetrahedron with three corner faces, with three secondary surfaces 37 _1-3 whose vertices 39 are located at the center of the triangle 25. Indicates what is provided. FIG. 2C shows a hexagonal longitudinal face 31, with six triangles having coplanar faces 41 _1-6 and a central vertex 43 _1-6 corresponding to vertex 39 in FIG. 2B. It is provided. The height of the vertices is determined as the workable height by a stamping technique on the metal sheet.

1 and 2A show two basic forms that a boss on an embossed wall of a hollow plate can take, and FIGS. 2B and 2C show that turbulence can be more smoothly formed in the air flow between the plates. The example of the deformable form of the principal surface which comprises a boss is shown.

FIG. 3 shows an AA ′ cross section of FIG. 1, showing an enlarged longitudinal cross-sectional view of one end of the hollow plate in a state before being joined to the manifold. FIG. This plate is the result of welding two walls 10a and 10b to each other. The wall 10b corresponds to the inversion of the head and the corners of the wall 10a about the transverse symmetry axis B-B '. . The cross section A-A 'is taken along the top of an alternating embossed portion formed by the projecting bosses 24 ₂ and the recesses 24' ₂ in row 14, and passes through the connecting portion 18 of the wall 10a. FIG. 4 is a cross-sectional view taken along the longitudinal central symmetry line C-C 'of FIG. 1, showing an enlarged view showing an end portion of a plate corresponding to the same portion as in FIG. 3.

In FIG. 3, the protruding boss and the concave portion according to the first embodiment of the lower wall 10b correspond to the upside of the upper wall 10a, wherein 24 ₂ and 24 ' ₂ portions of the upper wall 10a are illustrated in FIG. As can be seen from the side cross-section of 3, it is represented by recesses and protruding bosses, respectively. The protruding bosses 24 ' ₁ and the recesses 24 _{1 on the} wall 10b are nested in the recesses and the protruding bosses of the wall 10a, respectively. The portion 63 of the hollow plate inner channel is a portion located between the overlapping tops of the embossed portions of the plate, the thickness of which is 0.4 mm, and the portion 64 of the inner channel is raised and lowered at an angle of 45 ° of the protruding boss. It is a portion located between the inclined portions, the thickness is 0.28mm. The thickness of the inner channel 66 between the flat portions of the connections 18, 20 is 0.4 mm.

FIG. 3, which shows a right section along the line AA ′, shows (1) a starting portion 68 where the wall is gradually separated from the opposite conical portion 54-56 of the two walls 10a-10b and ends at the two connections, (2) two symmetrical steps of the wall starting from circles 58 ₂ and 58 ₁ , and (3) two symmetrical flanges 52 ₂ , 50 ₁ forming the sealing surfaces of walls 10a, 10b.

4 is a cross-sectional view along the longitudinal axis of symmetry CC ′, showing that the end of the hollow plate is joined to the slot 72 of the outer manifold and welded by the beads 70, wherein the slot 72 is 120 °. It is formed in the connecting shell 74 of the outer manifold 75 in the form of an arc, the outer manifold 75 is formed by welding two elongated shells to each other. According to the sectional view, two parallel portions 16a and 16b spaced apart at intervals of 0.4 mm to two portions corresponding to the narrow center portions of the walls 10a and 10b, and two corresponding to the opposite truncated portions of the walls 10a and 10b. The diffusion portions 54 and 56 are shown. The outermost gap of the diffusion portion is 3 mm, and the length of the 120 ° circular arc (60 ₂ , 60 _{3 in} FIG. 1) is 8 mm. As a result, the cross-sectional area of the straight section of the inner channel with the embossed wall and the cross-sectional area of the opening of the fin end are formed almost equal.

5 shows a heat exchanger 76 of the basic form consisting of fifteen thin hollow metal fins 78 _1-15 . As described above, the end of the hollow plate is welded to the circular slot, and the circular slots are 3.5 mm wide and are formed at 8 mm intervals, respectively, and are formed on the walls of the outer manifolds 80-82 formed in an aerodynamic shape. do. In order to facilitate the welding operation, the manifolds 80-82 are formed by welding two shells formed along a U-shaped cross section along a line 83. The shell is made of a metal strip formed by cutting the same sheet as is applied in the manufacture of plate walls. Half of these strips are slotted with the appropriate width, length and spacing, and the two types of strips thus prepared are the front cover and the connecting shell 75, respectively, using a matching template with protruding and concave profiles, Weld the opening of the plate to the slot of the connecting shell. Next, each of the two front lids is welded to a corresponding connecting shell, and then one side opening of each of the two shells is sealed, thereby forming two streamlined outer manifolds and the heat exchanger itself.

6 shows a plan view of the radiator 81 compactly formed. Six identical heat exchangers 76 _1-6 are mounted parallel to both sides of the two flat main manifolds 84, 86 arranged at right angles in the form of a right trapezoidal trapezoid, thereby providing adequate overall heat conduction. It can be a compact radiator with degrees. These flat manifolds 84, 86 have parallel planes 88 _1-2 , 90 _1-2 , and the thickness is formed to be approximately equal to the maximum dimension of the straight section cross section of the outer manifold 80 _1-2 . do. Two adjacent heat exchangers are arranged so that their cross sections are adjacent or slightly overlap with each other. The first embodiment includes circular openings 94 _1-6 and 96 ₁ in which portions of the upstream 80 _1-6 and downstream 82 _1-6 of the outer manifold are formed at equal intervals in the longitudinal direction of the main manifold. _-6 are welded to the same depth. In a second embodiment, there is a method of varying the insertion depth of the manifolds for odd and even rows of heat exchangers. The maximum distance between the two main manifolds parallel faces (88 ₂ -90 ₂₎ of the (84-86) is determined by the number of the heat exchanger (76) is mounted. The length of the shorter side of the main manifolds 84-86 is determined by the spacing of the outer manifolds 80-82 and the spacing 100 between the slopes 100 (typically 5 mm).

Thus, according to the heat exchanger assembly formed by stacking a hollow metal plate having a thin wall having improved rigidity by embossing, it becomes possible to construct a compact radiator which is particularly advantageous for cooling of a high performance (> 100 kW) heat engine. The radiator configured as described above has a very small cross-sectional area, high thermal conductivity, low power consumption for pumping and air circulation, and small volume and weight. It can also be suitably applied to exhaust gas cooling to improve performance in low speed operation of diesel engines. It is also generally applicable to any heat exchange between two fluids, especially liquids and gases, having large temperature and pressure differences (about 600 ° C., 1 MPa).

It is apparent that the present invention is not limited to the above embodiment. The width or length of the hollow plate may be much larger than that illustrated in FIG. 1, so measured in decimeters. The number of alternating bosses formed in each plate or the number arranged in each row may also be much larger than that illustrated in FIG. 1, and the maximum dimension of the plate may be determined with reference to the performance table of the available stamping press. The number of hollow plates placed in the heat exchanger can also be dozens, and the number of heat exchangers assembled in a compact radiator can also be dozens.

It is also possible to produce hollow plates according to the invention using two embossed walls which are similar but not identical with different transverse ends. In other words, instead of two identical walls having a step that is equal to half the thickness of the central inner channel, one wall forms a flange having a step that is twice that of the wall, and the other wall has a step. It is possible not to. According to this method, two sets of stamping molds are required, but the economic burden is not so great when the production rate is high.

The above figures show that for hollow plates for liquid / gas heat exchangers. The liquid is circulated through the narrow inner channel (0.3 mm) of the metal plate. In the case of gas / gas heat exchangers, the thickness of the internal channels is of course much larger (generally> 1 mm) and the spacing between the plates is smaller. This is because the mass flow rates and velocities of the two gases are almost the same on both sides of the hollow plate wall.

On the other hand, for certain applications, such as chemistry in which corrosive fluids are used, the application of high performance glass heat exchangers is desirable or needs to be considered. For this purpose a glass heat exchanger having a high volumetric conductivity can be provided, but the conductivity is about the middle of the single-plate polymer and the hollow plate heat exchanger (20 or 100 W / ° C.dm ³ ) made of the metal form according to the invention. . The maximum temperature and pressure difference applied to the glass heat exchanger is lower than the metal heat exchanger according to the invention can withstand, but is higher than the single piece polymer heat exchanger disclosed in the European patent of TET. For applications similar to the above, it may be desirable to apply a polymer heat exchanger having a volume conductivity of about 50% higher than a one-piece heat exchanger, while maintaining a range of pressure differentials and temperature differences. To this end, by adopting a new technology for the metal heat exchanger according to the present invention, it can be used through a hot stamping or thermoforming process for the polymer or glass sheet instead of the metal sheet. The two manufacturing processes are similar to each other, the former uses two molds and mechanical pressures with protrusions and recesses, the latter uses one mold and pneumatics, and both require proper heating. , Strain hardening does not occur.

As described above, the thickness of the wall and the inner channel of the glass or polymer hollow plate heat exchanger having the embossed wall and the outer manifold is inevitably large due to the mechanical properties of the applied polymer or glass, and their performance can be inferred from the foregoing description. have.

Claims (11)

A heat exchanger 76 having a low weight and volume, high volume conductivity, and applied to a fluid having a high pressure difference and a temperature difference, Metal hollow plates 78 _1-15 with narrow inner channels are arranged in layers at regular intervals and connected to outer manifolds 80, 82; The plate has an embossed central part (13), the central part being located between two connecting parts (18-20) having a narrow opening with an area corresponding to the cross-sectional area of the central part; The wall of the plate 78 is formed by stamping and cutting metal sheets; A heat exchanger in which side ends 42-44 of two walls 10-11 forming the hollow plate 78 are welded; The walls 10-11 of each hollow plate 78 _1-15 are formed of thin plates with rigidity, the embossing center 13 being aligned alternating bosses 22-22 ', 24-24'. One or more sets 12-14, wherein the alternating bosses have declination hard surfaces 26, 26, 28, 30 of steep slopes and are inclined and / or relative to the alignment lines of the bosses. Form a plurality of vertical pointed ends; The spacing 64-66 between the opposing faces is uniform and small and substantially constant with respect to the pressure difference applied; A narrow gap (78 _1-15 ) between the plates; In the heat exchanger derived from the heat exchanger of claim 1, Consists of a glass or polymer hollow plate having a thin inner channel and laminated to an outer manifold at regular intervals; The wall of the hollow plate is produced by a process of cutting after a heat stamping or thermoforming process; The plate has an embossed central part, the central part being located between two connecting parts 18-20 having a narrow opening with an area corresponding to the cross-sectional area of the central part; The side ends of the two walls forming said hollow plate are welded together; The central part of the plate comprises one or more sets of aligned alternating bosses, the alternating bosses having a steep strain hardening face, the plurality of inclined and / or perpendicular to the alignment lines of the bosses; Forming pointed ends; The spacing between the opposing faces is uniform and small and substantially constant with respect to the pressure difference applied; A narrow gap between the plates; The method according to claim 1 or 2, Each hollow plate 78 has at least two rows of alternating bosses 12-14; Two adjacent rows of alternating bosses are separated by narrow flat partitions 36 formed of two internal projections which are stamped or thermoformed and welded; The height of the protrusion corresponds to half of the maximum internal thickness of the hollow plate; The method according to claim 1 or 2, The angle formed by the vertical lines of the adjacent surfaces of the alternating bosses is at least 30 °, so that turbulence is effectively generated by the pointed ends between the surfaces and withstands the pressure difference between the fluids; The maximum angle formed by the vertical lines of the adjacent surfaces of the alternating bosses is limited to a limit value depending on the material to be stamped or thermoformed. The method according to claim 1 or 2, Said alternating bosses have two side faces 26 _1-2 , 26 ' _{1-2 in the} form of equilateral trapezoids sharing one longitudinal side 34 ₁ , 34' ₁ , and two central oblong share surface (30 ₂ -30 _'1) and; The length of the long diagonal of the oblong side corresponds to several tens of the thickness of the plate wall. The method according to claim 1 or 2, The alternating boss is an isosceles triangle (25'b _1-2 , 27'b ₁ ) in two sides and concave in the form of an isosceles triangle (25b _1-2 , 27b _1-2 , 29b _1-2 ) in the protruding boss. _-2 , 29'b _1-2 ) having two sides, and sharing two central hexagonal planes for the protruding bosses 22b _1-3 and the recesses 22'b _1-3 , The two central hexagons share a transverse edge; The spacing between the transverse edges of the central hexagonal surface corresponds to several tens of the thickness of the plate wall. The method according to claim 1 or 2, The embossed central portion 13 of each hollow plate is coupled to the outer manifold via two connections 18-20 having horizontal ends of the gently sloped walls that form the truncated portions 54-56. Heat exchanger characterized by the above. The method according to claim 1 or 2, Opposite surface of the hollow plate is provided with parallel walls, the interval separating the walls (64) is characterized in that the constant formed in the same order as the thickness of the wall. The method according to claim 1 or 2, A heat exchanger, characterized in that a plurality of secondary surfaces (37 _1-3 -41 _1-5 ) are formed on the symmetric boss surface and appear to be cut into diamond shapes (25-31), further comprising complementary pointed ends. The method according to claim 1 or 2, The outer manifolds 80-82 of the hollow plate are formed with an aerodynamic profile to minimize drag of the heat exchanger; Each manifold consists of two elongated shells, one of which shells 75 for connection of the plates, the other of which forms a front cover, the longitudinal section of the two shells being U Heat exchanger characterized in that the shape of the, fixed by the welding line (83). In a lightweight compact radiator with high thermal conductivity, -Two identical group heat exchangers 76 of heat exchangers with hollow plates made of metal, glass or polymer formed according to claim 5; The two groups are coupled to two upstream 84 and downstream 86 manifolds, the manifolds having a flat rectangular trapezoidal plane, with mutual spacing 100 so that the right corners are located opposite each other. Deployed; Each upstream 82 _1-6 and downstream 80 _1-6 manifold of each of the group heat exchangers has the main upstream downstream manifold at regular intervals slightly larger than the width of the central portion 13 of the heat exchanger. The radiator, characterized in that coupled to the corresponding surface of each.

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