JPH0566233B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a container for use in water heaters and the like.

(Prior Art) Conventionally, at the bottom of this type of container, a cylindrical body 31 and a bottom plate 32 are overlapped as shown in FIG. 6, and an end portion 33 is welded to the base metal.

(Problem to be Solved by the Invention) In this case, a V-shaped gap 34 is created in the overlapped portion, so even if stainless steel material is used, when boiling water, etc., corrosion occurs in the gap 34 and the bottom plate 32
The flat part of the welding was deformed by the heat during welding, making it difficult to achieve flatness.

In order to eliminate crevice corrosion, there was a method of butting the flange portion 35 of the cylindrical body 31 and the end face of the bottom plate 32, as shown in FIG. 7, and welding this butted portion. As shown, the weld 36
Since the wall thickness is thinner than other parts, minute cracks are likely to occur during cooling after welding, and this welded part is easily corroded, and the butt part has a gap due to thermal deformation during welding. This has the drawback that the work is extremely difficult because holes are sometimes formed, and the deformation of the flat part of the bottom plate 32 becomes even greater due to welding.

The present invention solves these problems by easily and reliably welding the container body and the bottom plate, increases corrosion resistance, eliminates distortion due to heat during welding, and is inexpensive. The purpose is to provide a container.

(Means for Solving the Problems) In order to solve the above-mentioned problems, the container of the present invention includes a cylindrical container body, a substantially dish-shaped flat portion connected to one end of the container body, and a planar portion around the cylindrical container body. The connecting portion is formed by fitting the outer periphery of the sloped wall of the bottom plate to one end of the container body from the outside, and welding this fitting portion to the base metal.

(Function) According to this configuration, the container body only needs to be flanged at the top opening, and the outer periphery of the inclined wall of the bottom plate is fitted from the outside at an acute angle to the lower end of the body of the cylindrical container, which is linearly welded. Since arc welding is performed from the outside with a welding torch, welding of the base metal is easy, there are almost no welding defects, and the flat part does not undergo thermal deformation due to welding. Furthermore, since the inner surface of the container is also easily melted, there are no gaps where corrosion is likely to occur, resulting in excellent corrosion resistance.

(Example) An example of the present invention will be described below in Figures 1 to 5.
This will be explained with reference to the figures.

In FIG. 1, 1 is an outer body, and a bottomed cylindrical container 5 is attached to a step 3 of a spout 2 placed on the upper end of the outer body 1 via a rubber packing 4, and a mounting bracket 6 is screwed to the bottom cover. 8 is a water level gauge provided through the side wall of the container 5, and 9 is a heating element attached to the lower outer bottom surface of the container 5, which has a water boiling heating circuit and a heat retention heating circuit. 10 is a thermostat that controls the energization of the hot water heating circuit, and 11 is a thermal reed switch that controls the heat generating circuit and maintains a constant temperature. 1
Reference numeral 2 denotes an upper lid, in which a bellows pump 13 is installed, air pressed by a push plate 14 is sent into the container 5 through an inner lid 15, and hot water in the container 5 is pumped through a suction pipe 16 and a discharge pipe 17. It is structured so that it pours out through the water. A seal packing 18 connects the bellows pump 13 and the inner lid 15 in an airtight manner.

As shown in FIG. 2, the container 5 is formed of a cylindrical container body 20 formed by rolling plate material into a cylindrical shape and arc welding the seam 19, and a bottom plate 21 made of plate material formed into a substantially dish shape. ing. This bottom plate 21
has a flat part 22, an inclined wall 23, and a mounting step part 24 for the heating element 9. Container body 20 and bottom plate 2
1 is connected to the container body 20 as shown in FIG.
A bottom plate having a sloped wall 23 with an outer diameter d slightly larger than D is placed on a portion of the diameter D of the inner surface of the lower end of the fourth
As shown in the figure, the outer periphery of the inclined wall 23 is brought into close contact with the inner surface of the container body 20 by pressing with the holding jig A to make the rising angle of the inclined wall 23 of the bottom plate 21 more β than α. At this time, the lower end surface of the container body 20 is made to protrude slightly x from the inclined wall 23. When a welding torch T is placed at this fitting part and an arc is generated, the x part of the protruding part of the container body 20 melts, and the outer periphery of the inclined wall 23 of the bottom plate 21 also melts, causing the base material to melt as shown in FIG. Welded. Thickness y of welded part 25
The material of the protrusion x of the container body 20 flows and is formed thicker than other parts. Also, container body 2
0 and the inclined wall 23 are more securely fitted due to the acute angle.

Therefore, there are no gaps on the inner surface of the container 5 that cause corrosion as in the conventional example, and since the container 5 has a sufficient wall thickness, welding cracks do not occur during welding and solidification. Further, when setting the bottom plate 21 to the container body 20, the inclined wall 23 serves as a guide, so that work efficiency is extremely good. Furthermore, as shown in FIG. 4, the angle of the inclined wall rises from α to β, and by the amount of repulsion, it firmly adheres to the inner surface of the container body 20, and since lateral pressure is applied, there is no misfitting.
It is also easy to reduce the wall thickness.

In addition, for parts other than the welded part, presser jig A, presser jig B,
Since it is pressed and fixed by the holding jig C, it is possible to restrict the heat of the welded part from being conducted to other parts, and welding defects due to the generation of fitting gaps do not occur. Also, bottom plate 21
Thermal deformation of the flat part 22 and the mounting step part 24 of the heating element 9 can be prevented. Therefore, since the thermal reed switch 11 and the heating element 9 are provided in close contact with the flat part 22 and the mounting step part 24, reliable temperature control with less variation is possible.

Furthermore, as shown in FIG. 4, when the presser jig C is provided with a hole 26 for supplying an inert gas such as argon and the welding part 25 is filled with the welding part 25, the welding part 25 is welded.
An oxide film is not formed on the inner surface 25a of the inner surface 25a, and surface treatments such as chemical polishing and electrolytic polishing are not required, resulting in lower costs. Particularly in this case, the inclined wall 23 of the bottom plate 21 and the container body 20 have an upper surface, a lower surface,
Since the side surface is cooled by the welding jig, it is highly effective in preventing the formation of an oxide film. In addition, the container body 20, the bottom plate 2
The plate material No. 1 has carbon content of 0.02% or less and chromium content of 15 to 20%.
% ultra-low carbon ferritic stainless steel containing
When a stainless steel plate containing 0.5 to 2.5% molybdenum and 0.2 to 1.0% niobium or titanium is used, corrosion resistance does not deteriorate even when heated by welding.

Further, since the welding part is the outer circumferential surface of the container body, welding can be performed even if the heating element 9 is attached in advance to the mounting step 24 of the bottom plate 21, and line formation can be made freely.

Furthermore, the container body is made by rolling a flat plate into a cylindrical shape and arc welding the seams, making it less expensive, and the use of bright material allows it to maintain its original luster. High quality can be obtained even without surface treatment.

(Effects of the Invention) As is clear from the above description, the container such as a water heater of the present invention has the following effects.

(1) Since the outer periphery of the sloped wall of the bottom plate is fitted into the container body from the outside, the sloped wall acts as a guide and improves workability. In addition, since the welding part is fitted at an acute angle, welding workability is good and it is easy to melt all the way to the inner surface.

(2) Since the outer circumference of the inclined wall is press-fitted with the outer circumference slightly larger than the inner diameter of the container body, the angle of the inclined wall can be automatically adjusted, and the outer circumference of the inclined wall is in perfect contact with the inner surface of the container body, there is no welding defect, and the wall thickness is improved. It is also easy to make the wall thinner.

(3) Since the sloping wall absorbs strain, deformation of the flat surface and mounting steps can be prevented, and the thermal reed switch and heating element are installed in close contact with each other, ensuring reliable installation and less temperature variation. Can be controlled.

(4) Since the parts other than the welded parts are sealed and fixed by presser jig A, presser jig B, and presser jig C, inert gas such as argon supplied through the hole in presser jig C is used. When welding is performed by filling the welding area with gas, no oxide film is formed on the inner surface of the welding area, and surface treatment such as chemical polishing or electrolytic polishing is not required, resulting in lower costs. In this case, since it is cooled by the holding jig, the effect of preventing the formation of an oxide film is particularly large.

(5) The wall thickness of the welded part is thicker than that of other parts due to the flow of material from the protruding part of the container body, so there is no gap on the inside of the container that can cause corrosion, and there is sufficient wall thickness. Because it is thick, welding cracks do not occur and the container has extremely high corrosion resistance.

(6) Since the welding of the container body and bottom plate is done at the outermost edge, parts can remain attached to the bottom plate, making line organization easy.

(7) The body of the container is made by rolling a flat plate into a cylindrical shape.
Since the process is simply arc welding of the seams, it is inexpensive, and if bright material is used, the original gloss can be maintained, resulting in a high-quality product even without surface treatment.

It has the above-mentioned effects, and its industrial value is extremely great.

[Brief explanation of the drawing]

Fig. 1 is a partially cutaway sectional view of an electric water heater using a container showing one embodiment of the present invention, Fig. 2 is a perspective view of the same container, and Figs. 3 and 4 are the same. FIG. 5 is an enlarged cross-sectional view of the main part of the container after welding, and FIGS. 6, 7, and 8 are partial cross-sectional views of the conventional container. It is a diagram. 20... Container body, 21... Bottom plate, 22... Flat part, 23... Inclined wall, 25... Welded part.

Claims (1)

[Claims] 1 Consisting of a cylindrical container body and a bottom plate that is connected to one end of the container body and has a substantially dish-shaped flat part and an inclined wall around the bottom plate, and the connecting part is connected to one end of the container body. The bottom plate having an outer diameter slightly larger than the inner diameter of the one end is press-fitted from the outside, and the tip of the one end of the container body and the tip of the inclined wall of the bottom plate are welded to the base metal. Containers such as water heaters.