JPH0442597B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a plate-like hollow body having a cavity for passing a fluid, preferably liquid heat medium, and a plate-like hollow body thermally connected to a steel wall and protruding from the same wall. , at least one heat transfer plate made of a metal having a thermal conductivity greater than that of steel, the heat transfer plate being crimped to the hollow body by a material welded to the hollow body; The present invention relates to a heat exchanger, in particular a heater or a heat sink.

This type of heat exchanger has a heat dissipation surface (for example, in the case of a heater) or a heat absorption surface (for example, in the case of a heat sink).
This has the advantage of being very significantly increased compared to heat exchangers consisting only of hollow bodies. The effect of a heat exchanger plate is the greater the stronger the heat flow through the plate. This heat flow depends firstly on the thermal conductivity and secondly on the cross-sectional area of the heat exchanger plate.

Known heat exchangers of the type mentioned at the beginning (DE-U-
1938253), the heat exchanger plate is fixed by a tongue-like piece welded to the plate-like hollow body. These tongues pass through slits in the heat exchanger plate and are bent or held through fixing members. This type of connection does not provide intimate contact between the heat exchanger plate and the hollow body such that satisfactory heat transfer between the hollow body and the heat exchanger plate occurs. Known heat exchangers also require significant manufacturing costs;
This is because many individual tongues have to be welded to the hollow body.

In the case of another known heat exchanger (DE-Al-2315035), aluminum fins formed from serpentine bent sheets are arranged between parallel iron or copper tubes. The lamellas are joined to the parallel tubes by solder. The heat exchanger formed in this manner has a high capacity considering its size because aluminum has extremely good thermal conductivity. However, they are expensive to manufacture and complicated due to the brazing methods that must be used.

In addition, a method of joining layers by welding (DE-
Al-2723072) is also known and with this method materials that cannot be directly welded together can be welded together. For this purpose, a hole is made in one layer, a ball made of a material weldable with the other layer is introduced into the hole, and this ball is then welded to the latter layer, thereby making the hole Crimp the layer with the opening to the other layer. This publication does not describe the manufacture of heat exchangers.

Finally, it is known to weld together thin sheets provided with an aluminum layer (SCHWEISS TE
−CHNIK, Band22, Haft8, 1972, Berlin, J.
SZYMANSKI“Punktschweissen aluminierter
Bleche im Stahlbau” Seiten 361-362). In this case, electric resistance welding is applied and the aluminum layer is first melted, so that the steel cores of the thin sheets are in direct contact with each other. The extremely thin aluminum layer is a self-supporting structural part. Rather, it is firmly bonded to the thin steel plate by diffusion of aluminum into the steel.There is also no suggestion in this publication of the manufacture of heat exchangers.

The invention is based on the problem of configuring a heat exchanger of the type mentioned at the outset in such a way that a good heat transfer connection between the heat exchanger plate and the hollow body is obtained with low manufacturing costs. .

The present invention proposes two means for solving the above problems.

One of them is that the material welded to the hollow body consists of a thin steel plate lying on a heat exchanger plate, which is penetrated in several places and welded to the hollow body by spot welding. It is characterized by

Another solution is that the material welded to the hollow body
consisting of steel particles, such as punch pieces or shavings;
Several steel particles are welded to a steel hollow body by spot welding and are simultaneously embedded in a heat exchanger plate, characterized in that the melting point of the heat exchanger plate is lower than the melting point of the steel particles. It is said that

In the case of both of the above solutions, a very economical spot welding method is used to achieve a very welded crimping of the heat exchanger plate to the plate-shaped hollow body, which results in very good heat transfer. It will be done.

In the case of the first solution, it is possible to use a pre-drilled heat exchanger plate and to make the holes through the heat exchanger plate by melting using the heat generated by the welding current. be. Preformed holes have the advantage that no welding of the heat exchanger plates is necessary and a very durable bond between the strip and the steel wall is obtained. Particularly when the sheet metal strips are pushed into the holes by means of welding electrodes, welding and thus thermally conductive contact of the heat exchanger plate to the steel wall can be achieved even with large manufacturing tolerances for the hole diameter and spacing. If the heat exchanger plate is perforated by melting, the deposited steel sheet has a very strong contact with the heat exchanger plate, which results in very good conduction from the steel wall to the heat exchanger plate. The advantage is that heat is achieved. If the heat exchanger plate must be penetrated during welding, the melting point of the heat exchanger plate is lower than the melting point of the steel (at least about 50°C). This condition applies in particular to aluminum and aluminum alloys. Through-melting of the heat exchanger plates can be achieved without additional operations using welding electrodes which, after through-melting, effect the welding between the strip and the steel wall. In other fastening methods, the melting point of the heat exchanger plate may be higher than the melting point of the steel.

The heat transfer plate is preferably made of aluminum or an aluminum alloy.

The thermal conductivity of ordinary steel is about 40 W/mK, and the thermal conductivity of special stainless steel is only about 15 W/mK. On the other hand, the thermal conductivity of aluminum is approximately 200W/
mK, which is five times the thermal conductivity of ordinary steel. In other words, even with a predetermined thickness, five times as much energy is transmitted through an aluminum plate as compared to a steel plate.

This greatly increases the efficiency of the heat exchanger plate,
Consequently, the capacity of the entire heat exchanger is also increased. Also, the combination of steel walls and aluminum heat exchanger plates has no problems in terms of corrosion. Although aluminum and steel are far apart in terms of the electrochemical series of metals, this is not a disadvantage. This is because there is generally no electrolyte between the hollow body and the heat exchanger plate. Even if electrolyte in the form of perspiration water should occasionally form under unfavorable installation conditions, this is in no way dangerous to the tightness of the hollow body. This is because the base metal, ie aluminum, is sacrificed, which may corrode the heat exchanger plates, but not the hollow pairs. The combination according to the invention is also advantageous compared to known aluminum heaters, since the hot water contacts only the steel and therefore the steel pipes and pipes can be directly connected to the heater or other heat exchanger without any drawbacks. This is because it can be connected. With the heat exchanger according to the invention, there is thus no need for intermediate joints of plastic parts in the pipes to be connected, as would be necessary due to corrosion considerations when using aluminum heat exchangers. According to the present invention, the heat exchanger plate can be made significantly longer than when using a steel plate.
This is because, for example, in the case of a heater, a large amount of heat is still transferred in the area of the heat exchanger plate that is far away from the point of contact with the steel plate, and even there there still exists a temperature difference with respect to the environment that allows a significant heat exchange. It is from. The invention is not limited to the use of aluminum as the thermally conductive material. Other metals with good thermal conductivity are also suitable, such as many aluminum alloys and copper.

If aluminum plates are used, their wall thickness for the heat exchanger plates is between 0.1 and 0.9 mm, very preferably between 0.3 and 0.5 mm. Such a wall thickness gives the heat exchanger plate relatively great stability and has a thermal conductivity comparable to a steel plate with a thickness of 1.5 to 2.5 mm. However, due to the high thermal conductivity, heat exchanger plates thinner than 0.3 mm can also be used. A protected arrangement of the heat exchanger plates is advantageous in this case to avoid deformations.

When using a thin steel plate, manufacturing is easier if the heat exchanger plate is provided with protrusions and the protrusions are fitted into the recesses of the thin steel plate to position the thin steel plate on the heat exchanger plate. become.

It is advantageous for the welding crimping of the heat exchanger plate to the steel wall if the steel sheet has approximately the same thickness as the heat exchanger plate. Therefore, selection of such a thickness is recommended.

The heat exchanger according to the invention can be realized using several individual heat exchanger plates and one or more large interconnected heat exchanger plates. For good heat conduction in the two embodiments, it is advantageous to shape the heat-absorbing or heat-releasing surface to be as large as possible. Particularly when using sheet steel, serpentine bent heat exchanger plates are advantageous. This is because this shape of the heat exchanger plate provides lateral fixation of the steel sheet without additional costs during manufacture.

Next, embodiments of the present invention will be described with reference to the drawings.

The heat exchanger according to FIG. 1 has a hollow body 1 and a heat exchanger plate 2 thermally connected thereto. The heat exchanger plate 2 has a rectangular shape as shown in FIG. The hollow body 1 is made of steel and may, for example, consist of two shells welded together at their respective edges, as shown in FIGS. 13 and 14. On the other hand, the heat exchanger plate 2 is
Made of other materials with a thermal conductivity greater than that of steel. Aluminum and aluminum alloys are preferred. In the following, it is assumed that aluminum heat exchanger plates are used in the illustrated embodiment. Aluminum and steel cannot be welded together as is well known. Therefore, the structure described below was applied to obtain a bond with good thermal conductivity.

All heat exchanger plates have side pieces 2a parallel to the hollow body 1.
and a side piece 2b protruding from the hollow body.
In the embodiment according to FIG. 7, the side piece 2a has a hole 3
has. A strip-shaped thin plate 4 is applied onto the side piece 2a. In every hole region, the strip has a recess 5 which passes through the arranged hole 3 and is connected to the hollow body 1 by spot welding. The welded portion is indicated by 6.

The side piece 2a is closely pressed onto the hollow body 1 by means of a strip 4, so that a good thermally conductive connection is obtained. Welding is performed using welding electrodes 7 and 8,
These electrodes are in contact with the hollow body during welding.

Welding electrodes 7, 8 are shown in a retracted state. During the welding operation, the electrode 8 is attached to the thin strip 4, and the electrode 7
is crimped to the hollow body 1. The electrode 8 also forms a depression. The thin strip 4 is also flat in the area of the hole 3 before the electrodes are crimped.

In the embodiment according to FIG. 8, a strip 4 is likewise used for fixing the side piece 2'a of the heat exchanger plate, but the side piece 2'a does not have pre-drilled holes. Doesn't exist. The strip 4 is connected to the steel wall of the hollow body 1 by welding the side pieces 2'a through at the welding points. A hole 9 is similarly generated during this through melting, but its wall is not cylindrical but has a flat hollow conical shape. In this case as well, the thin strip 4
is pushed in (indentation 10), but the indentation is flatter. Since the formation of the holes 9 takes place by melting, the hole walls 9a are adapted to the shape of the depressions 9 and a very strong contact is created. The actual welding area is indicated by 11. For welding, spot welding electrodes 7 and 8 (shown slightly pulled back) are used here as well.

In the embodiment according to FIG. 9, steel particles are embedded in the side piece 2''a. These steel particles are welded to the steel wall 1, for example to the wall of the hollow body. In some cases, steel particles, which may consist of scrap material, are sprinkled onto the side piece 2''a. The welding electrodes 7 and 8 are crimped together, the heat exchanger plate material is first softened by heating with a welding current, and the particles 12 are press-fitted into the softened material. These steel particles naturally have a significantly higher melting point than heat exchanger plates made of aluminum. Eventually at least some particles 12 will come into contact with the steel wall 1 and welding will be achieved. In this case, the welding location is indicated by 13. The embodiment according to FIG. 9 has the advantage that it does not require special strips as used in the embodiments according to FIGS. 7 and 8.

3 to 6 illustrate other shapes of the heat transfer plate. FIG. 3 shows the web 20a and the side pieces 20b, 2.
A U-shaped heat exchanger plate 20 with 0c is shown. web 2
0a may be connected to the hollow body 1 in the manner described with reference to FIGS. 7-9. FIG. 4 shows a heat transfer plate 21 having a flat side piece 21a and a shaped side piece 21b. The side piece 21a may be fixed as described above. The shape of the side piece 21b enlarges the surface compared to a flat side piece. Such surface enlargement is advantageous because heat transfer in aluminum is good.

FIG. 5 shows a heat exchanger plate 22 having a hat-shaped cross section. This cross-section differs from that according to FIG. 3 by the provision of edge bends 22c and 22d at the ends of the side pieces 22a and 22b. FIG. 6 shows the fixed piece 23a, whereas FIG. 12 shows the state after welding. In this respect, the first
Figure 2 corresponds to Figure 7. FIG. 13 again shows the state before welding. In order to facilitate a precise positioning of the steel strip 18 relative to the heat exchanger plate, projections 24 are provided on the heat exchanger plate in the heat transfer region 16, which fit into corresponding recesses 25 in the strip 18 by pressing. FIG. 14 shows the state after welding.
The projections and depressions 24, 25 may also be compressed and smoothed during welding. However, it may also be omitted.

The hollow body 15 is composed of two outer skins 26 and 27. Here, the member to which the heat exchanger plate is fixed does not necessarily have to be a hollow body. For example, it is also possible to electrically heat the fixed sheet steel wall of the heat exchanger plate, in which case a hollow body through which the fluid heat medium passes is not necessary.

The height of the bent portion is represented by b (FIG. 11), and the thickness of the heat exchanger plate is represented by a. For a given heat exchanger plate thickness a, the height b may be significantly larger than the effective value, even if the heat exchanger plate is made of steel. Due to the extremely good thermal conductivity of aluminum, even with relatively large heights b, a large amount of heat is still conducted into the outer region of the bend, where there still exists a noticeable temperature difference with respect to the ambient air.

FIG. 15 shows a structure which corresponds in principle to the structure according to FIGS. 10-14. Figure 15 shows the steel wall 2
8 shows that heat exchanger plates 29 or 30 or 31 of different heights h ₁ , h ₂ or h ₃ can be fixed. In this case as well, fixing by means of applied strips 32 is used. Since the sections of heat exchanger plates of different heights are the same, the same steel wall 28 can be used for all these heat exchanger plates. The selection of a suitable heat exchanger plate is made depending on the temperature difference occurring as well as the desired efficiency of the heat exchanger.

FIG. 16 illustrates that a large connected heat exchanger plate may also be shaped so that its surface is enlarged. Two hollow bodies 3 and 34 are shown, and heat transfer plates 35 are fixed to mutually opposing surfaces of these hollow bodies. The heat transfer plate 35 has a heat conduction area 36 in contact with the hollow bodies 33 and 34.
has. These heat exchanger plates are also fixed to juxtaposed hollow bodies using applied steel strips.
Between the two heat transfer regions there is a bend 38 projecting from the hollow body. The bend is again shaped in a serpentine manner by means of the concave shape 39, so that its surface and thus also its contact area with the ambient air is significantly enlarged. In this way also the good thermal conductivity of aluminum can be fully exploited. This structure is also advantageous when the height of the heat exchanger plate is set and a sized surface of the heat exchanger plate is desired.

FIG. 17 shows a retaining plate 41 made of steel on a steel wall 40.
is fixed, and then an embodiment in which an actual heat transfer plate 42 made of aluminum is bonded to the holding plate will be shown.

The holding plate 41 is curved in a meandering manner, and the fixing area 4
3, it is connected to the steel wall 40 by a spot weld 44. Between the two fastening areas 43 extends a bend 45 with a flat wall 45a to which the heat exchanger plate is attached. The heat exchanger plates are 10th to 14th.
It is formed as shown in the figure and is similarly fixed using a strip-shaped steel sheet 18. In this embodiment, the holding plate 41 also has a heat transfer function, since heat has to be transferred from the steel wall 40 to the heat exchanger plate 41. Since the environmental air also flows over the retainer plate 41, it receives heat directly from the retainer plate as well.

[Brief explanation of drawings]

FIG. 1 is a perspective view of a heat exchanger with a hollow body wall and several angular heat transfer plates fixed therein, and FIGS. 2 to 6 are angular heat transfer plates used in the heat exchanger according to FIG. Cross-sectional views of various shapes of plates; FIG. 7 is a partial sectional view in the fixing region of the hollow body and the heat exchanger plate when the applied thin steel plate is pushed through the holes of the heat exchanger plate; FIG. 8 is a sectional view corresponding to FIG. 7 of the fixation zone when the heat exchanger plate is melted through, and FIG. 9 is a cross-sectional view corresponding to FIG. 7
8 is a cross-sectional view, FIG. 10 is a perspective view of a heat exchanger using large connected heat exchanger plates bent in a serpentine shape, and FIG. 11 is a hollow body with heat exchanger plates. Fig. 10 is a cross-sectional view of the heat exchanger before fixing, Fig. 12 is a cross-sectional view corresponding to Fig. 11 showing the heat exchanger plate after fixing, and Fig. 13 is before fixing. 14 is a longitudinal sectional view corresponding to FIG. 13 in the fixed state (FIG. 12), and FIG. 15 is a longitudinal sectional view of the heat exchanger according to FIG. FIG. 16 is a cross-sectional view of a heat exchanger with two hollow bodies and a large heat exchanger plate fixed to these and having shaped bent parts. FIG. 17 is a cross-sectional view of the heat exchanger when the connection according to FIGS. 7 to 13 is carried out using retaining plates: 1, 15 ... hollow body, 2, 20 ,21,22,
23, 14, 29, 30, 31, 35, 42...
Heat exchanger plate, 2a, 2′a, 2″a, 20a, 21a,
22a, 23a... side piece of heat exchanger plate, 3, 9...
Hole, 4, 18, 32, 37... Strip steel thin plate, 7,
8... Welding electrode, 12... Steel particles, 16, 36...
...Top part, 17, 38...Bending part, 24...Protrusion,
25... recess, 28, 40, 33, 34... steel wall, 41... retaining plate.

Claims (1)

[Scope of Claims] 1. A plate-shaped hollow body made of a steel plate 1; 15; 28; 40 having a cavity for passing a fluid heat medium therethrough and thermally connected to a steel wall and protruding from the same wall. , at least one heat exchanger plate 2; 20 made of a metal having a thermal conductivity greater than that of steel;
21;22;23;14;29;30;31;3
5; has 42; heat exchanger plate 2; 20; 21; 22;
23; 14; 29; 30; 31; 35; 42 welded to hollow body 1; 15; 28; 40 material 4;
Hollow body 1; 15; 2 by 18; 32; 37
8; 40, the material welded to the hollow body 1; 15; 28; 40 is crimped to the heat exchanger plate 2; 20;
3; 14; 29; 30; 31; 35;
The heat exchanger, characterized in that it is welded to the hollow body 1; 15; 28; 40 by. 2. The heat exchanger according to claim 1, wherein the heat exchanger plate 2a; 14 is perforated and the thin steel plate 4; 18 passes through the heat exchanger plate with holes 3; 9. 3 The heat transfer plate 2'a is melted and the thin steel plate 4
The heat exchanger according to claim 1 or 2, wherein the melting portion 9 penetrates the heat exchanger plate 2'a, and in this case, the melting point of the heat exchanger plate 2'a is lower than the melting point of the thin steel plate 4. . 4 Heat exchanger plate 2; 20; 21; 22; 23; 14;
3. A heat exchanger according to any one of claims 1 to 3, wherein 29; 30; 31; 35; 42 are made of aluminum or an aluminum alloy and have a thickness of 0.1 mm to 0.9 mm. 5. The heat transfer plate 14 is provided with a protrusion 24, and the protrusion fits into the recess 25 of the thin steel plate 18 in order to orient the thin steel plate 18 on the heat transfer plate 14. The heat exchanger according to any one of items 4 to 4. 6 Steel thin plate 4; 18; 32; 37 is heat transfer plate 2; 1
4; 29; 30; 31; 35; 42. 7 Heat exchanger plate 14; 29; 30; 31; 35; 42
has several bends 17; 38 and is connected to the steel walls 27; 28; 33; 34 or to the steel walls along the tops 16; 36 of the bends 17; 41, in this case the steel thin plate 4;1
8; 32; 37 has the width of the top portion 16; 36. Heat exchanger according to any one of claims 1 to 6. 8 A plate-shaped hollow body 1 made of a steel plate having a cavity for passing a fluid heat medium and a steel wall that is thermally connected to and protrudes from the same wall, and has a thermal conductivity higher than that of steel. A heat exchanger having at least one heat exchanger plate 2''a made of a metal having In the container, the hollow body 1
The welded material consists of steel particles 12, several steel particles are pressed into the heat transfer plate 2''a during spot welding and welded to the steel hollow body 1, and at the same time are embedded in the heat transfer plate 2''a. At this time, the melting point of the heat exchanger plate is steel particles 12
The heat exchanger is characterized in that the melting point of the heat exchanger is lower than the melting point of the heat exchanger.