KR100388044B1 - Panel of solar collector and apparatus for manufacturing the same - Google Patents

Abstract

The present invention relates to a heat collecting plate of a solar heat collector and a manufacturing apparatus thereof, and an object thereof is to provide a heat collecting plate that is easy to manufacture and has a low price, and particularly has excellent heat collecting efficiency. It's about having it.

Therefore, in order to achieve the above object, the present invention, the upper and lower plates (10, 20) coupled by the upper and lower spot welding (32, 132) to form a flow path (30, 130) flowing therein ) 110, 120, and the upper and lower edges 10, 20, 110, and 120 of the corner portions are joined by seam welding 134, while the upper and lower plates 110 and 120 are provided. The flow passage 130 provides a heat collecting plate (1) (100) of the solar collector is formed in a continuous integral curve.

In addition, the guide member 210 for guiding the sides of the heat collecting plate (1) (100) having a thickness of 0.35-0.7mm for this purpose, and the drive member installed on the upper and lower sides to move the heat collecting plate (1) (100) ( 220, upper and lower electrodes installed to spot weld the upper and lower plates 10, 20, 110, and 120 at a constant current A1, welding pressing force P1, and a constant energization time T1. Spot welding means (230) having a (232, 234), and the upper and lower heat collecting plate 10 with a constant current (A2) and welding pressing force (P2), constant conduction time (T2) and constant connection diagram (V2) It provides a heat collecting plate manufacturing apparatus of a solar heat collector comprising a seam welding means 240 having upper and lower electrode rolls 242, 244 installed to seam the edge portion of the (20) (110) and (120). .

Description

Collector of solar collector and its manufacturing apparatus {PANEL OF SOLAR COLLECTOR AND APPARATUS FOR MANUFACTURING THE SAME}

The present invention relates to a heat collecting plate of a solar heat collector, and more particularly, to provide a heat collecting plate which is easy to manufacture and has a low price of heat collecting plate, and particularly has excellent heat collecting efficiency, as well as to provide a manufacturing apparatus of the heat collecting plate. It relates to a heat collecting plate and a manufacturing apparatus thereof.

In general, Teyang heat is an infinite amount of residual amount, there is no use cost, but a low energy density energy source, a device that collects such solar heat efficiently absorbs and collects the solar heat for heating applications in general homes, etc. It is called a collector, and in order to use solar heat efficiently, a collector is required to have a low cost and high efficiency.

That is, the efficiency of the solar collector is determined by the heat collecting plate installed in the collector, the heat absorbing function of the solar heat is determined, the heat medium inside the heat collecting plate is heated by the heat collecting plate that is absorbed and heated by the heat collecting plate excellent in solar heat absorption, such heating The heating medium is heated or supplied by heating the heating or hot water while repeating the heating process, such a heat collecting plate is usually a flat plate, vacuum tube and concentrated type, etc., in terms of economics is widely spread flat plate collecting plate.

At this time, it is important that the heat transfer of the heat medium in the heat collecting plate is transferred from solid to liquid by convection, so that the contact area between the heat collecting plate and the heat medium increases the solar heat absorption efficiency, especially when the vortex of the heat medium is severely generated, It is increased.

One of the heat collecting plates of such a conventional solar collector is disclosed in US Pat. No. 4108159 and shown in FIG.

That is, the heat collecting plate 300 disclosed in the US patent is a combination of the copper pipe 320 by brazing (BRAZING) on the galvanized steel sheet 310, such a conventional heat collecting plate 300 is on the galvanized steel sheet 310 Due to the brazing of the copper tube 320, the contact area of the heat medium flowing in the copper tube 320 is small, and thus, the absorption efficiency of solar heat is weak. In particular, the bonding of the copper tube 320 and the steel plate 310 is poor or corrosion, etc. If this occurs, there is a problem that the heat transfer efficiency is extremely reduced.

In addition, another conventional heat collecting plate is disclosed in another US Patent No. 4010733 and shown in FIG.

That is, the heat collecting plate 400 disclosed in the other US patent is a metal plate 410 is assembled by spot welding and seam welding. In the other conventional heat collecting plate 400, the spot welding of the heat collecting plate 400 As a result, the flow path 410 ′ of the heat medium formed on the metal plate 410 is formed in a straight line, that is, the heat medium vortex phenomenon is reduced in the heat collecting plate 400, which in turn increases the heat absorption efficiency of the heat collecting plate due to the vortex of the heat medium. There is a problem such that the heat collection efficiency of the solar collector as a whole is lowered.

The present invention has been made in order to improve the various problems as described above, the object of the present invention is to increase the heat collection efficiency by expanding the contact area between the heat medium and the heat collecting plate flowing inside the heat collecting plate of the solar collector and heat transfer by heat medium flow turbulence In addition, the present invention provides a solar heat collecting plate for improving the heat absorption efficiency of the heat collecting plate.

In addition, another object of the present invention is to facilitate the manufacture of a heat collecting plate having a curved flow path or spot-welded at a predetermined position, so that the workability as well as the manufacturing and installation of a solar heat collector of the solar collector, which is easy to manufacture and install the device as a simple structure. It is to provide a device.

1 is a schematic view showing a heat collecting plate of a conventional solar collector

Figure 2 is a schematic diagram showing a heat collecting plate of another conventional solar collector

Figure 3 (a) and (b) is a schematic plan and front cross-sectional view showing a heat collecting plate of the solar collector according to the present invention

4A and 4B are schematic plan and front cross-sectional views showing another heat collecting plate of the solar heat collector according to the present invention.

5 and 6 are a plan view and a front view showing a heat collecting plate manufacturing apparatus of the solar collector according to the present invention

7 is a graph showing the relationship between welding current and weld strength;

(A)-(c) is a principal part state diagram which shows the heat collecting plate welding state by the welding current of the heat collecting plate manufacturing apparatus of the solar heat collector of this invention.

Explanation of symbols on the main parts of the drawings

1,100 .... heatsink 10,110 .... tops

20,120 .... lower 30,130 .... Euro

32 .... spot welds 34 .... seam welds

200 .... Heat collecting plate manufacturing device 210 .... Guide member

220 .... driving member `230 .... spot welding means

232,234,242,244 .... upper and lower electrode (roll)

240 .... Seam welding means

As a technical aspect for achieving the above object, the present invention, the upper and lower plate is coupled to the upper and lower spot welding to form a flow path flows therein, the upper and lower edges of the lower plate is seam welding In the heat collecting plate of the solar heat collector coupled to both sides of the flow path supply and discharge pipes, respectively, the upper and lower plates, the upper and lower plates are composed of a steel plate having a thickness of 0.35-0.7mm, the flow path flows therein In order to increase the heat transfer efficiency due to the expansion of the contact area between the heat medium and the heat collecting plate and to improve heat transfer due to heat flow turbulence, the spot welding is formed in a single curved shape along the curved flow path. Placed By providing a heat collecting plate of the solar collector, characterized in that.

In another aspect, the present invention, the heat collecting plate of the solar collector of the upper and lower plate having a thickness of 0.35-0.7mm, the guide member for guiding the side of the heat collecting plate,

A driving member installed above and below the heat collecting plate so as to move;

Spot welding means having the upper and lower electrodes that are installed to spot weld the upper and lower plates in a constant current (A1) and the welding pressing force (P1), and a constant conduction time (T1),

Seam welding means having upper and lower electrodes to seam the edges of the top and bottom panels of the heat collector at a constant current (A2), welding pressing force (P2), constant conduction time (T2), and constant connection degree (V2). By providing a heat collecting plate manufacturing apparatus of the solar collector is configured.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Figure 3 (a) and (b) is a schematic plan view and a cross-sectional view showing a heat collecting plate of the solar collector according to the present invention, Figure 4 (a) and (b) is another heat collecting plate of the solar collector according to the present invention 5 and 6 are plan and front structural views showing a heat collecting plate manufacturing apparatus of a solar heat collector according to the present invention.

In FIG. 3, the first heat collecting plate 1 of the present invention is illustrated. The heat collecting plate 1 is coupled to the upper and lower plates 10 and 20 by the overlapping welding operation described below. The flow path 30 is formed to allow the heat medium to flow therein, thereby enabling a substantial solar absorption function.

At this time, the flow path 30 is formed by overlapping the upper and lower plates 10 and 20 formed with semicircular arcs 12 and 22 having a continuous cross section, and the welding operation of the heat collecting plate 1 described above is large. Spot welding work for spot welding the upper and lower plates 10 and 20 at various points of the upper and lower plates 10 and 20 and sealing the edges of the upper and lower plates 10 and 20 to prevent leakage of the heat medium. It is divided into seam welding to prevent.

That is, the first heat collecting plate 1 of the present invention is located at the half arc-shaped interface of the upper and lower plates 10 and 20 when the spot welding 32 of the upper and lower plates 10 and 20 is viewed diagonally in cross section. In the end, the heat collecting plates 10 and 20 are heat welded therebetween by spot welding 32 welded at a predetermined interval and direction without the need to form a specially shaped flow path 30. While forming a severe vortex flows inside the heat collecting plate (1) to improve the heat collecting efficiency.

Meanwhile, the edges (edges) of the heat collecting upper and lower plates 10 and 20 are closely welded to the seam welding 34, and the important part is the steel plate thickness of the upper and lower plates 10 and 20.

That is, the upper and lower plates 10 and 20 should be formed of a steel plate having a thickness of 0.35-0.7 mm, wherein the plate thickness is smaller than 0.35 mm, although not shown in the drawing, the outer edge of the heat collecting plate 1 In order to prevent radiant heat loss and to prevent contamination, that is, contamination of the surface of the heat collecting plate 1 and lowering the absorption efficiency of solar heat, glass is installed to make the heat collecting plate 1 sag, making it difficult to maintain the gap with the glass. Deterioration of the heat collection efficiency, and at the same time there is a problem that the cosmetic contact or hole is generated because the deviation is easily generated during welding.

On the contrary, when the thickness of the upper and lower heat collecting panels 10 and 20 is larger than 0.7 mm, the heat collecting efficiency, which is the most important function of the light collecting plate 1, is substantially lowered, and the total weight of the heat collecting plate 1 is increased so that The construction work is difficult, and there is a problem of increasing the production cost.

Meanwhile, the heat supply and discharge pipes 36a and 36b are connected to both sides of the flow path 30 of the upper and lower plates 10 and 20, respectively, and the seams to which the upper and lower plates 10 and 20 are coupled. The outer part of the welding 34 is provided with a plurality of fixing rings 38 to facilitate the movement and construction of the heat collecting plate 1.

Next, FIG. 4 illustrates a second heat collecting plate 100 of the present invention. The biggest feature of the heat collecting plate 100 is that the upper and lower plates 110 and 120 as described above overlap each other, and thus, spot welding 132. ), And when combined with the seam welding 134 of the edge portion, the flow path 130 formed between the upper and lower plates 110 and 120 is integrally formed in a continuous curve.

Therefore, the heat medium flowing through the integral successive curved flow path 130 flows inside the heat collecting plate 100 through a larger vortex as compared with the conventional straight flow path, which expands the heat collecting plate contact portion of the heat medium. By improving the heat transfer by the flow turbulence to improve the heat collecting efficiency of the second heat collecting plate 100 of the present invention.

In addition, the upper and lower plates 110 and 120 of the heat collecting plate 100 are also composed of a steel plate having a thickness of 0.35-0.7 mm, and the reason thereof is as described above. By using (steel material), the heat collecting plates 1 and 100 can be installed to reduce costs.

In addition, similar to the first heat collecting plate 1, the second heat collecting plate 100 also has heat supply and discharge pipes 136a and 136b connected to both sides of the flow path 130 of the upper and lower heat collecting panels 110 and 120, respectively. The outer portion of the seam welding 134 to which the upper and lower plates 110 and 120 are coupled is integrally provided with a plurality of fixing rings 138 to facilitate the movement and construction of the heat collecting plate 100.

At this time, the spot welding and seam welding of the heat collecting plate (1) 100 as described above is important, which will be described in detail in the following heat collecting plate manufacturing apparatus (200).

Next, FIGS. 5 and 6 illustrate the present invention heat collecting plate manufacturing apparatus 200. The heat collecting plate manufacturing apparatus 200 as described above has an upper and lower plates 10 and 20 having a thickness of 0.35-0.7 mm as described above. (110) 120 is a device for manufacturing a heat collecting plate (1) (100).

In addition, looking at the configuration of the heat collecting plate manufacturing apparatus 1 in detail, the guide member 210 for guiding the heat collecting plate (1) (100), the drive member 220 for moving the heat collecting plate (1) (100), Spot welding means 230 for spot welding the upper and lower plates 10, 20, 110 and 120, and seam welding the corners of the upper and lower plates 10, 20, 110 and 120 Seam welding means 240 is largely divided, looking at each of them in detail as follows.

As shown in FIG. 5, the guide member 210 guides the sides of the heat collecting plate 1 and 100 undergoing welding to maintain a surface of rubber to accurately maintain the transfer of the heat collecting plate 1 and 100. Although not shown in detail in the drawings, it is a guide roll that is installed in a vertical direction so that the position can be adjusted according to the width of the heat collecting plate (1) (100) contact guides.

Next, FIG. 5 illustrates a driving member 220 installed above and below the heat collecting plate 1 and 100 so that the driving member 220 is in contact with the top and bottom surfaces of the heat collecting plate. It is configured as a possible driving roll, and the lower side of the both sides of the heat collecting plate (1) (100) is provided with a plurality of L-shaped bent guide plate 22 arranged in sequence to both sides of the heat collecting plate (1) (100) Prevent edges from sagging.

Next, FIG. 6 shows the spot welding means 230 installed to spot weld the upper and lower plates 10, 20, 110 and 120, wherein the spot welding means 230 is the heat collecting plate ( 1) The upper and lower electrodes 232 and 234 for direct contact with the upper and lower plates of the 100 are provided.

At this time, the upper electrode 232 of the spot welding means 230 is installed in the lower portion of the cylinder 238 vertically installed at a predetermined interval on the moving bar 236 installed to move left and right schematically shown in FIG. The lower electrode 234 of the spot welding means 230 is fixedly installed under the heat collecting plate.

Accordingly, the upper electrode 238 conducts spot welding while energizing the arrayed lower electrode 234 as the cylinder 238 moves up and down and moves the left and right movement bars 236. 234 is installed at all of the spot weldable positions of the heat collecting plates 1 and 100 and should be adjusted to perform welding when energizing the upper electrode 232.

In addition, the spot welding means 230 is a current collector (A1) of 2-10KA, 50-500 kgf of welding pressure (P1), and 5-20 cycles of energization time (T1) of the heat collecting upper and lower plates 10 (20) (110) 120 is spot welded.

At this time, if the current of the spot welding means 230, that is, the current (A1) applied when energizing through the upper and lower electrodes is less than 2KA, as described above, when the thickness of the upper and lower heat collecting plates is at least 0.35mm Even if the weld is not formed sufficiently, on the contrary, if the current is larger than 10KA, even when the maximum thickness of the upper and lower plates of the collector is 0.7 mm, the molten metal is scattered due to overheating, which lowers the working environment and reduces the quality of the welded part.

In addition, when the welding pressing force P1 is less than 50 kgf, the contact between the upper and lower plates during welding is applied to the cylinder 238 that applies the pressure of the welding pressing force P1, that is, the upper and lower electrodes 232 and 234. This becomes poor and a gap phenomenon occurs between the upper and lower plates, which may cause a short circuit in the welded part. On the contrary, when the welding pressing force P1 is larger than 500 kgf, the contact force between the upper and lower electrodes 232 and 234 is increased. This is larger than necessary to generate a power loss, the indentation of the weld is generated thick, rather there is a problem that causes deformation of the spot welding (32, 132).

In addition, if the energization time T1 of the spot welding is less than 5 cycles, in this case, the amount of heat input is also reduced, resulting in poor spot welding. On the contrary, if it is larger than 20 cycles, the strength of the weld is not increased even if the energization time is longer. Rather, there is a problem that causes power consumption and electrode wear phenomenon.

Next, FIGS. 5 and 6 show seam welding means 240 sealing the edge portions of the heat collecting plate 1 and 100 through the spot welding described above to prevent leakage of the internal heat medium. The 240 also includes upper and lower electrode rolls 242 and 244 for welding the heat collecting upper and lower plates during energization.

In addition, the welding means 240 is installed in front of the spot welding means 230, which is to perform seam welding of the edge portion after performing the spot welding of the upper and lower plates of the heat collection.

On the other hand, the upper electrode roll 242 of the seam welding means 240 is also installed on the lower portion of the cylinder 246 installed perpendicular to both ends of the heat collecting plate, which is to apply a constant welding pressing force as described above, on the contrary The lower electrode roll 244 is fixedly installed on the lower side of the heat collecting plate.

At this time, the seam welding means 240 is a current (A2) of 10-20KA, welding pressing force (P2) of 400-700 kgf, the energization time (T2) of the on / off 2-5 / 1-3 cycle and At the welding speed (V2) of 0.5-5 m / min, the edges of the top and bottom plates 10, 20, 110 and 120 should be seam welded.

That is, the seam welding means 240 as described above also has a suitable condition, that is, the current A2 of 10-20KA, the welding pressure P2 of 400-700 kgf, and on / off, as well as the spot welding means 230. Seam welding of the edges of the upper and lower plates 10, 20, 110 and 120 at the collector current (T2) and welding speed (V2) of 0.5-5 m / min Do it.

At this time, the range of the above conditions is larger than the spot welding because the seam welding operation closely welds the upper and lower plates of a larger portion. If the current (A2) applied to the electrode during welding is less than 10KA, the amount of heat input Insufficient welds are not formed due to lack, and on the contrary, when larger than the current A2 of 20KA, molten metal is scattered or welded cracks are generated due to excessive heat input.

In addition, when the welding pressing force P2 is smaller than 400 kgf or larger than 700 kgf, as in the spot welding operation described above, the contact area is reduced due to the shunt phenomenon in which the welding part is short-circuited due to the amount of contact and the contact area is reduced. Excessive power consumption and indentation of the welded parts will be caused.

In addition, in the energization time (T2) of less than 2 cycles, the amount of heat input is insufficient, so that the weld portion is not sufficiently formed. If the temperature is larger than 5 cycles, the indentation of the weld portion and the electrode revolving steel sheet are not supplied and the electrode is not supplied. The appearance occurs.

In addition, less than 1 cycle means continuous energization, and the above-described heat input amount is excessive. If the heat cycle is larger than off 3 cycles, the heat input amount is insufficient, resulting in a problem in that the welding part is not sufficiently formed.

On the other hand, if the welding speed (V2) by the vertical electrode roll 242, 244 of the seam welding means 240 is less than 0.5m / min, cracks and deformation of the weld portion is severely generated by overheating heat, conversely 5m If it is larger than / min, the amount of heat input is insufficient, so that it is difficult to form a welded portion and a relatively large capacity welder is required, thereby increasing the installation cost.

Accordingly, the cycle that is the unit of the energization time T1 (T2) of the spot welding means 230 and the seam welding means 240 is a unit of 1/60 seconds, and thus the energization time is applied while being switched on and off. The energization time controls the amount of heat input, but the actual welding work is performed continuously.

Hereinafter, embodiments of the present invention will be described.

7 is a graph showing the relationship between the current (A1) and the welding pressing force (P1) and the energization time (T1) during the spot welding operation, wherein the heat collecting upper and lower plates 10, 20 ( It is a condition of spot welding of 110) and 120. If the welding current is less than 4KA in the case of 15 cycles of energization time, it can be seen that welding is not performed. Even if the welding current is increased above 4KA, the weld strength does not increase. It can be seen that the weld strength was maintained at 4KA or more at the welding pressure, that is, 200kgf, but the weld strength was maintained at 5KA or more at the high pressure of 300kgf.

Therefore, the spot welding of the heat collecting plate (1) (100) by the spot welding means 230 is the current (A1) of 2-10KA, the welding pressing force (P1) of 50-500 kgf, and energization of 5-20 cycles It can be seen that it is suitable to be carried out at time T1.

Next, the seam welding state is shown in (a)-(c) of FIG. 8, that is, when the thickness of the top and bottom plates is 0.7 mm, the welding pressing force P2 of 500 kgf and the on 2 / off 2 cycle are shown. 12KA, assuming an energization time of T2 and a welding speed of 2 m / min (V2). The seam welding condition of 15KA and 18KA is shown.

Therefore, as can be seen in Figure 8a, when less than 12KA it can be seen that the welding heat is insufficient due to the low heat input current, and also as shown in Figure 8c, when larger than 18KA, the internal pores in the welding portion due to excess heat And it can be seen that the surface cracks are generated, and as shown in Figure 8b it can be seen that the best seam welding site was formed in the case of 15KA, so that the seam welding of the upper and lower heat collection of 0.35-0.7mm is 10- 20KA current (A2), 400-700 kgf welding pressure (P2), energization time (T2) of on / off 2-5 / 1-3 cycle and welding speed (V2) of 0.5-5 m / min It is most appropriate when performed as.

On the other hand, each of the welding means 230, 240 is a hydraulic unit 260 such that the power supply unit 150 and the cylinder 238, 246 for applying a proper current is operated at an appropriate pressure as shown in FIG. ) Are each connected.

As described above, according to the heat collecting plate of the solar heat collector, the heat collecting efficiency is improved by expanding the contact area between the heat medium and the heat collecting plate flowing in the heat collecting plate and improving heat transfer due to the heat flow turbulence, thereby improving the solar heat absorption efficiency of the heat medium, thereby improving the operability of the heat collecting plate. Has the effect of improving.

In addition, it is to provide an excellent effect that the low-cost steel sheet to bend the heat medium flow path of the heat collecting plate by spot welding and seam welding, or to produce a heat collecting plate by spor welding.

While the invention has been shown and described with respect to specific embodiments thereof, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit or scope of the invention as set forth in the claims below. I would like to know that those who have knowledge of this can easily know.

Claims (8)

delete delete The upper and lower plates 110 and 120 are coupled to the upper and lower spot welding 132 to form a flow path 130 through which a heat medium flows, and corner portions of the upper and lower plates 110 and 120 are seams. In the heat collecting plate 100 of the solar collector coupled to the welding 134, the heat supply and discharge pipes (136a, 136b) are respectively connected to both sides of the flow path 130 of the upper and lower plates 110 and 120, The upper and lower plates 110 and 120 are made of a steel plate having a thickness of 0.35-0.7 mm, and the flow path 130 is used to enlarge the contact portion between the heat medium and the heat collecting plate therein and to improve heat transfer due to the heat medium flow turbulence. Successive integral curves are formed to increase the heat collection efficiency, and the spot welding 132 is integrally curved along the curved flow path 130. Placed Collector plate of the solar collector, characterized in that The heat collecting plate of the solar collector, characterized in that a plurality of fixing rings (138) is installed on the outer portion of the seam welding (134) to which the upper and lower plates (110, 120) are coupled. In the heat collecting plate (1) (100) of the solar collector of the upper and lower plates 10, 20, 110, 120 of the steel sheet having a thickness of 0.35-0.7 mm, Guide member 210 for guiding the side of the heat collecting plate (1) (100); And, A drive member 220 installed above and below the heat collecting plate 1 and 100 to move; The upper and lower electrodes 232, which are installed to spot weld the upper and lower plates 10, 20, 110, and 120 at a constant current A1, the welding pressing force P1, and a constant energization time T1. Spot welding means 230 having a 234; And, Installation of the edges of the upper and lower plates 10, 20, 110, and 120 for seam welding with a constant current (A2), welding pressing force (P2), constant conduction time (T2), and constant connection degree (V2) The collector plate manufacturing apparatus of the solar heat collector, characterized in that consisting of seam welding means 240 having upper and lower electrode rolls (242, 244) The lower electrode of claim 5, wherein the upper electrode 232 of the spot welding means 230 is installed at a lower portion of the cylinder 238 vertically arranged at a predetermined interval on the left and right moving bars 236. 234 is fixedly installed on the lower side of the heat collecting plate, The spot welding means 230 is a current collector (A1) of 2-10KA, the welding pressing force (P1) of 50-500 kgf, and the energizing time (T1) of 5-20 cycles, the upper and lower plates 10, 20 ) 110, 120, the heat collecting plate manufacturing apparatus of the solar collector, characterized in that it is configured to spot welding The upper electrode roll 242 of the seam welding means 240 is installed in a lower portion of the cylinder 246 perpendicular to both ends of the heat collecting plate, and the lower electrode roll 244 is lower than the heat collecting plate. Fixedly installed in the The seam welding means 240 is a current (A2) of 10-20KA, welding pressing force (P2) of 400-700 kgf, the energization time (T2) and 0.5- of the on / off 2-5 / 1-3 cycle The heat collecting plate manufacturing apparatus of the solar heat collector, characterized in that the edge portion of the heat collecting upper and lower plates 10, 20, 110, 120 are seam welded at a welding speed V2 of 5 m / min. The method of claim 5, wherein the guide member 210 is formed of a vertical guide roll that is installed to guide the side of the heat collecting plate, the drive member 220 is configured as a driveable drive roll in contact with the upper and lower surfaces of the heat collecting plate And a plurality of bent guide plates 22 supporting the lower side edge portions of the heat collecting plate are installed.