JP2002062085A - Heat-exchange fin for brazed-plate heat exchanger, and heat exchanger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide heat-exchange fins for a brazed-plate heat exchanger, and a corresponding heat exchanger. SOLUTION: A fin (9) includes a perforated and/or recessed corrugated product, which has a main direction of corrugation (F1), which is bounded by two lateral edges (13). The main direction of the corrugation (F1) is oblique with respect to the two lateral edges (13).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

FIELD OF THE INVENTION The present invention relates to a brazing plate heat exchanger of the type having a corrugated main direction, defined by two lateral edges, and having a perforated and / or recessed corrugated product. Heat exchange fins.

[0002]

BACKGROUND OF THE INVENTION The present invention is applied, for example, to a main heat exchange line of an air distillation plant. This heat exchange line brings the incoming air and the resulting cold product from the air distillation column into a heat exchange relationship. Brazed plate heat exchanger can provide a large heat exchange area with small capacity,
Furthermore, since it is relatively easy to manufacture, it is widely used. These heat exchangers are often made of aluminum or aluminum alloy and are composed of a plurality of parallel and substantially rectangular plates, between which corrugated spacers or fins of various geometries are formed. However, on the other hand, a bar is arranged for closing the flat-shaped fluid flow path defined by the plate. These flows may be countercurrent, cocurrent or crossflow.

[0003] The function of the fins is to increase the heat exchange area and thus improve the overall heat exchange performance. In particular, these fins conduct the heat flux by conduction to adjacent plates attached by brazing. The fins are manufactured very inexpensively from folded, perforated, recessed and / or stamped flat materials. The basic waveform has a substantially square, rectangular or triangular cross section. In other words, the known fins are a single corrugated sheet “straight corrugated”, “perforated corrugated”, “herringbone corrugated” having a corrugated bus, and “louver corrugated” having corrugated legs with concave portions. The lateral deviation of the waveform is formed at regular intervals along the generatrix, and this deviation is known as a "sawtooth waveform" or "partially biased waveform" which is approximately half the period of the waveform. .

[0004]

In these known fins, the main direction of the waveform which is the average direction of the waveform in the case of the Herringbone waveform defines the direction of the minimum resistance to the flow of the fluid.

[0005] In each flow path of the exchanger, a major part in the length direction of the flow path constitutes an actual heat exchange section to which fins called heat exchange fins are attached. In some cases, the heat exchange section is separated by fluid inlet and outlet distribution sections attached to distribution fins.

The heat exchange section is separated by two horizontal closure bars parallel to the two opposite ends of the plate. The main direction of the corrugation of the heat exchange fins is a small number in the case of a limited area where this main direction is perpendicular to the transverse closure bar (so-called "double-cross" arrangement) in order to cause a local pressure drop. Parallel to these closure bars, with the exception of The following description does not touch the fins.

In the distribution section, the fins have an average direction of the waveform which is greatly inclined with respect to the waveform of the heat exchange fins. It is an object of the present invention to improve the simplicity of brazing plate heat exchangers by improving their thermal performance.

[0008]

In order to achieve such an object, the object of the present invention is a heat exchange fin of the type described above. This heat exchange fin has a main direction of the waveform that is oblique to the two lateral ends, and the fin has an overall direction of least resistance to fluid flow substantially parallel to the two lateral ends. , Wherein the fluid flow is substantially parallel to the two lateral edges.

It is also an object of the present invention to have a plurality of parallel rectangular plates, which have a generally flat channel between the plates and a horizontal closure bar between the two plates in each channel. And a fin that forms a spacer together with a brazing plate heat exchanger of which the heat exchange fins are defined as described above.

An example illustrating the present invention is shown with reference to the accompanying drawings.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The heat exchanger 1 shown in FIG. 1 is, for example, a cryogenic heat exchanger. This exchanger is formed by stacking parallel rectangular plates 2. These rectangular plates 2
Define a plurality of flow paths for fluids, all equal, between which an indirect heat exchange relationship is created. In the example shown, these channels are continuous and circulating with the channel 3 for the first fluid, the channel 4 for the second fluid, the channel 5 for the third fluid. It is a target.

Each of the channels 3 to 5 is delimited by a plurality of lateral closure bars 6 and a plurality of end closure bars 7 which define the channels and free the corresponding fluid inlet / outlet windows 8. Corrugated spacers that act as spacers between the plates, as heat fins, and as a means to guide fluid flow, especially while brazing, to prevent deformation of the plates when pressurized fluid is used Alternatively, corrugated fins are arranged in each channel. These fins are heat exchange fins 9 over substantially the entire length of the flow path. In these areas adjacent to the window, these fins 9 are extended by distribution fins 10. The latter either distributes the fluid coming in from the inlet window over the entire width of the fin 9, or collects the fluid in the outlet window over such full width.

Generally, the stacked plates, closure bars, and corrugated spacers are formed of aluminum or aluminum alloy and are assembled in a single operation by oven brazing. A fluid inlet / outlet box 11 having the overall shape of a half cylinder is then welded to the exchanger body, thus forming a corresponding row of inlet / outlet windows 8 entirely. These boxes 11 are connected to a fluid supply and discharge pipe 12.

FIG. 2 schematically shows one of the flow paths of the same exchanger, flow path 3. The heat exchange fins 9 are typically between 1 ° and 30 °, preferably between 2 ° and 10 °, with respect to the longitudinal direction F2 of the channel, which is the longitudinal direction of the transverse closure bar 6, It has a main direction F1 of a waveform forming a positive acute angle α.

However, the arrangement of the fins 9 is such that all directions of minimum resistance to the fluid in the flow path are substantially in the direction F2. Furthermore, FIG.
Shown are two distribution fins 10 adjacent to the exit window 8. The angle β formed by the waveforms of these distribution fins with respect to the direction F2 is considerably larger than the angle α, and is typically close to 75 °. All directions of minimum resistance to flow are
The main direction of the corrugations, and thus the distribution fins may perform the distribution function.

The fins 9 are formed from a fold sheet material. This longitudinal direction is perpendicular to F1. This material, after being folded, is cut along two lines 13 parallel to the direction F2, and thus has the shape of a parallelogram (for one or more intermediate sheets) or a rectangular trapezoid or a right-angled triangle. Shape (in the case of two end sheets), several, corrugated sheets 14.
3 to 8 show three different embodiments of the fin 9.

In the embodiment of FIGS. 3 and 4, the fins have corrugated grooves 1 joined together by corrugated legs 17.
5 and a waveform 16 having a rectangular cross section.

Each leg 17 is provided with an opening 18 which is folded at the side of the leg which receives the fluid flux (the left hand side in FIGS. 3 and 4) at regular intervals. These openings 18 open toward the upstream of the flux. Thus, as shown by the arrow in FIG.
The fluid flow guided between the two legs 17 in the direction of F 1 is partially deflected transversely to the direction by the openings 18.

Thus, the direction of the minimum resistance to flow of the fins 9 is generally in the direction of F2 when the shape and dimensions of the openings 18 are appropriately selected. In addition, the F1 tilt and opening 18 provide the flow with a two-dimensional, turbulent configuration. This form of turbulence allows for effective heat exchange.

In the embodiments of FIGS. 5 and 6, the fins are of the "saw" type. The fins thus have alternating lateral offsets d on one side as well as on the other side at regular intervals along a direction F1 called the "saw-like longitudinal direction" 1 . This offset is approximately equal to half the distance between the two legs 17, called the "separation distance" p . Thus, the fin has a parallel displacement plane P, which forms a parallel displacement line 19 when viewed from above (FIG. 4).

Each leg 17 has a tip bent at right angles over its entire height, thus defining a deflection tab 20. All tabs 20 are oriented on the same side, i.e. on the side of the leg 17 which receives the flow of fluid.
The tab 20 has the effect of reducing the flow area for the fluid on the side where the tab is provided and the effect of increasing the flow area on the opposite side. Thus, FIG.
As shown in the figure, in each flow of the fluid guided between the two legs 17, there is seen a flow in a direction close to F2 or in a direction inclined with respect to F2 opposite to F1.

Due to the turbulence generated in the fluid, as described above, the fins 9 can, by appropriate selection of the fin parameters and the dimensions of the tub 20, change the direction of least resistance to flow near F2. Have. 7 and 8, the tabs 20 are omitted and the legs 17
Is different from the prior art in that a concave portion 21 is provided along a predetermined front end and a predetermined rear end. In particular, the latter alternately has a recess and a non-recessed portion at both its leading and trailing ends for every other row of legs 17.

The legs 17 alternately have concave portions 21 at their leading ends and concave portions at their rear ends in the middle row. As a result, these effects are basically the same as described above with respect to FIGS.

[Brief description of the drawings]

FIG. 1 shows a brazing plate heat exchanger according to the invention,
It is shown in a perspective view, partially in section.

FIG. 2 shows a flow path of the present heat exchanger.

FIG. 3 is a perspective view showing a part of a fin according to the present invention.

FIG. 4 is a cross-section taken along the center plane IV of FIG. 3, showing similar fins.

FIG. 5 is a perspective view showing another embodiment of the fin of the present invention.

FIG. 6 shows the fin of FIG. 5 in section along the center plane IV of FIG. 5;

FIG. 7 is a perspective view showing yet another embodiment of the fin of the present invention.

FIG. 8 shows the fin of FIG. 7 sectioned at the center plane VIII of FIG. 7;

[Explanation of symbols]

3, 4, 5 ... flow path, 8 ... window, 9 ... fin, 10
... distribution fins, 11 ... boxes, 13 ... lateral ends.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Etienne Warren 75015 Paris, France Boulevard Pasteur 85 F-term (reference) 3L103 AA05 AA35 BB13 BB27 BB50 CC18 CC22 DD15 DD22 DD52 DD55 DD57 DD58

Claims (11)

[Claims] 1. A corrugated product having holes and / or recesses, the corrugated product having a main direction of the corrugation (F).
In a heat exchange fin for a brazing plate heat exchanger of the type defined by two lateral edges (13) having a 1), the main direction of the corrugation (F1) is relative to the two lateral edges A fin characterized by being inclined. 2. The method according to claim 1, wherein said fluid flow has a general direction of least resistance (F2) to said fluid flow, said fluid flow being substantially at an angle to the main direction of the waveform (F1). The fin of claim 1, wherein 3. Fin according to claim 2, characterized in that the general direction (F2) of the least resistance to fluid flow is substantially parallel to the two lateral edges (13). 4. An outer portion (1) at a corrugated leg (17).
8; 20; 21), characterized in that the profile effects the movement of the fluid transversely to the general direction (F2) of the least resistance to flow. 5. The fin according to claim 1, wherein the corrugated leg has an outer portion for forming a turbulent flow of a fluid. 6. The outer shape portion (18) has a wavy leg (1).
7. The fin of claim 4 or claim 5 comprising an opening in the side of 7), wherein the corrugated legs receive a flow of fluid and the plurality of openings are open upstream of this flow. . 7. The contoured portion comprises a tab (20) projecting from the side of a corrugated leg (17), wherein the corrugated leg receives a flow of fluid and is saw-toothed. A fin according to claim 4 or claim 5. 8. The tab (20) has a corrugated leg (17).
The fin according to claim 7, wherein the fin is provided at a tip of the fin. 9. The wavy leg (17) comprises recesses (21) on the leading and / or trailing ends of the corrugated legs (17), the recesses being defined by the lateral edges as compared to the main direction of the waveform (F1). The fin (9) is provided on the correction line (19) so as to be able to enlarge the area of the fluid flow in a direction approaching the direction (F2) of (13), and is a saw-type. Item 4 or 5 fin. 10. A plurality of parallel rectangular plates (2) which define between them a generally flat channel (3, 4, 5). In each channel, the heat exchange fins (9), together with the lateral closure bar (6),
A brazed plate heat exchanger of the type forming a spacer between two plates, wherein at least one heat exchange fin (9)
Is a heat exchanger according to any one of claims 1 to 9. 11. The heat exchanger according to claim 10, comprising a main heat exchange line of an air distillation plant.