JPH0152114B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing heat exchangers for water heaters and other heat exchangers.

Conventionally, in this type of heat exchanger, a heat absorbing body consisting of a plurality of heat absorbing fins arranged side by side is inserted into the heating cylinder, and after this is bonded to the heating cylinder, plating such as lead plating is applied to improve durability. In this case, the heat absorbing body and the heating cylinder are formed by connecting the edge of each heat absorbing fin c of the heating cylinder a and the heat absorbing body b inscribed therein, as shown in FIGS. 1 and 2. After setting the brazing material d in advance and temporarily attaching the appropriate heat absorbing fin c to the heating cylinder a at the part indicated by A in the figure by torch brazing or ultrasonic welding, the brazing of each part of the heat exchanger is carried out. Generally, they are bonded together by furnace brazing.

Setting the brazing material d between the heating cylinder a and each heat-absorbing fin c and bonding them together by furnace brazing is possible if all the heat-absorbing fins c are connected to the heating cylinder one after another by torch brazing or ultrasonic welding. If the weld is made to bond to the heat absorbing fin c and the heating cylinder a, heat conduction from the welding point will cause a gap due to thermal distortion at the welding point between the heat absorbing fin c and the heating cylinder a, which will be welded later, and if this continues, the plating will be difficult, This is because hot combustion air leaks through this gap during use, resulting in poor heat exchange efficiency. Note that if a special ultrasonic welding machine is used to weld each heat absorbing fin c to the heating cylinder a at the same time, the heating cylinder a and each heat absorbing fin c will be bonded without any gaps, and there will be no solder between them. Although it is no longer necessary to set the material d, it is necessary to prepare a plurality of welding machines depending on the type of heat exchanger, which increases equipment costs. By the way, when the heat exchanger is used, the heat absorption fins are heated by the hot combustion air from the burner below them, and since the heat absorption fins are fitted with heat absorption pipes through which heat medium such as water flows, the temperature of the heat absorption fins is The part below the pipe insertion part becomes hotter than the part above. In this case, when the heat absorbing fin is brazed to the heating cylinder in a furnace, the brazing material melts and the heat absorbing fin reaches the heating cylinder over the entire width of its edge. As a result, heat tends to escape from the lower part of the heat-absorbing fin, which is heated to a high temperature, to the body, resulting in poor heat exchange efficiency.

In view of the above points, the present invention improves productivity by eliminating the need to set a brazing material between the heating cylinder and the heat absorbing fins, and provides a versatile and heat-generating device that can easily cope with model changes. The purpose of this is to provide a method for manufacturing a heat exchanger that can also improve exchange efficiency. In the method for manufacturing a heat exchanger, in which a plating treatment is performed after bonding to the heating cylinder, the heat absorbing body is bonded to the heating cylinder by inert gas arc welding only at the upper part of each heat absorbing fin. It is characterized by

Next, the present invention will be explained with reference to embodiments shown in FIG. 3 and below.

In the drawing, 1 indicates a heating cylinder, and 2 indicates a heat absorbing body inserted into the heating cylinder 1. The heat absorbing body 2 is a heat absorbing pipe 4 in which a plurality of heat absorbing fins 3 are arranged side by side and a heat medium is flowed therethrough.
The heat absorber 2 is inserted into the heating cylinder 1.
The heating cylinder 1 is inserted and set on the welding table 5 as shown in the third figure, the heating cylinder 1 is pressed from both sides by the work pushers 6, and while the table 5 is moved back and forth, a pair of For example, TIG welding torch 7 for inert gas arc welding,
7, the upper part of the joining edge of each end of each heat absorbing fin 3 to the heating cylinder 1 is connected to the heating cylinder 1 as shown in FIG.
Welded in sequence.

The welding torch 7 is equipped with a nozzle 7a at the tip that spouts inert gas, and operates to perform arc welding in an inert gas atmosphere with a tungsten electrode 7b inserted through the nozzle 7a.
are cooled by the inert gas to prevent thermal distortion due to heat conduction to other parts, and thus each heat absorbing fin 3 is connected to the heating cylinder 1 at the upper part of its joint edge.
are welded sequentially without any gaps.

Thereafter, piping members are attached to the heating cylinder 1 and these are brazed in a furnace. At this time, there is no need to set a brazing material between the heating cylinder 1 and each heat absorbing fin 3 as in the above conventional example. During the plating process, there is no problem in which the plating becomes poor.

Incidentally, when changing the model, the position of the welding torch 7 may be adjusted vertically and horizontally according to the model.

By the way, when each heat absorbing fin 3 is welded to the heating cylinder 1 only at the upper part of the joining edge as described above, there is a small gap between the lower part of the joining edge and the heating cylinder 1 due to the surface roughness of the opposing surfaces of the two. Although a large number of fins remain and the adhesion between the two deteriorates to some extent, this effectively functions to suppress the escape of heat from the lower part of the heat-absorbing fin 3 heated to a high temperature to the heating cylinder 1.

As described above, according to the present invention, the heat absorbing body inserted into the heating cylinder is bonded to the heating cylinder by inert gas arc welding at each heat absorbing fin, and the occurrence of thermal distortion is prevented by the cooling effect of the inert gas. The heat absorbing fins and the heating cylinder are sequentially welded without any gaps, and the plating process can be performed well without setting a brazing material between them and bonding them together by furnace brazing. Productivity is improved by eliminating the setting work, and it is also possible to easily change the model of the heat exchanger.Furthermore, since each heat absorption fin is welded to the heating cylinder only at its upper part, the heat absorption fins that are heated to high temperatures are It has the effect of suppressing the escape of heat from the lower part of the fin to the heating cylinder and increasing heat exchange efficiency.

[Brief explanation of drawings]

Figure 1 is a perspective view of a heat exchanger explaining the conventional method;
Fig. 2 is a cutaway side view of the joint between the heat absorbing fin and the heating cylinder, Fig. 3 is a perspective view of an example of the apparatus used to carry out the method of the present invention, and Fig. 4 shows the heat absorbing fin and the heating cylinder for explaining its operation. FIG. 3 is a cutaway side view of the joint portion with the heating cylinder. 1... Heating cylinder, 2... Heat absorbing body, 3... Heat absorbing fin.

Claims (1)

[Claims] 1. In a method for manufacturing a heat exchanger, in which a heat absorbing body consisting of a plurality of heat absorbing fins arranged side by side is inserted into a heating cylinder, the heat absorbing body is bonded to the heating cylinder, and then plating treatment is performed. A method for manufacturing a heat exchanger, characterized in that the body is bonded to the heating shell by inert gas arc welding only at the upper part of each heat-absorbing fin.