JPH0423525B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a container for a water heater or the like.

BACKGROUND ART Conventionally, the bottom of this type of container was made by overlapping a cylinder 31 and a bottom plate 32 as shown in FIG. 6, and welding the end 33 to the base metal.

Problems to be Solved by the Invention In this case, a V-shaped gap 34 is created in the overlapping part, so even if stainless steel material is used, when boiling water, etc., corrosion will occur in the gap 34, and the flat part of the bottom plate 32 will be damaged during welding. It had the disadvantage that it was deformed by the heat of the heat, making it difficult to obtain flatness.

In order to eliminate crevice corrosion, there was a method of abutting the flange portion 35 of the cylinder 31 and the end face of the bottom plate 32 and welding this abutted portion as shown in FIG. 7, but in this case, as shown in FIG. As the wall thickness of the welded part 36 is thinner than other parts, minute cracks are likely to occur during cooling after welding, and this welded part is easily corroded. Due to the gaps, holes are likely to occur during electric arc welding, making the work extremely difficult, and the bottom plate 3
The problem was that the deformation of the planar portion of No. 2 was even larger. The present invention is intended to solve these problems, and aims to provide a container that facilitates and reliably welds the container body and bottom plate, improves corrosion resistance, and is free from distortion due to heat during welding. It is.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention comprises a cylindrical container body and a substantially dish-shaped bottom plate consisting of a flat part and an inclined wall, and the inner diameter of the container body is D. If the angle of inclination of the bottom plate is d, then D > d when inserting the bottom plate into the end face of the container body, and D < d by reducing the slope of the inclined wall during welding. The base metal is welded.

Function According to this configuration, the bottom plate can be inserted into the end face of the container body from the inside diameter D of the container body to the outside diameter d of the inclined wall of the bottom plate.
Since the diameter is small, it can be easily set, and when welding, by placing it on the sloped wall of the bottom plate with a welding jig, D < d, and the end face of the sloped wall of the bottom plate can be press-fitted to the inner surface of the container body, making it easy to weld the base metal. Therefore, there are almost no welding defects and no deformation occurs due to the heat during welding. It also has excellent corrosion resistance, with no gaps where corrosion is likely to occur.

Embodiment Hereinafter, an embodiment of the present invention will be described in FIGS. 1 to 5.
This will be explained with reference to the figures.

1 to 5, 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. , 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 hot water heating circuit and a heat retention heating circuit.

10 is a thermostat that controls the energization of the 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, which has a bellows pump 13 installed inside, and air pressed by a push plate 14 is sent into the container 5 via the inner lid 15, and the hot water in the container 5 flows into the suction pipe 1.
6. The liquid is poured out through a discharge pipe 17. A seal packing 18 connects the bellows pump 13 and the inner lid 15 in an airtight manner.

The container 5 is formed by rolling a plate material into a cylindrical shape, arc welding a seam 19, and comprising a cylindrical container body 20 and a bottom plate 21 formed from the plate material into a substantially dish shape. This bottom plate 21 has a flat part 22 and an inclined side wall 23.
and a mounting step portion 24 for the heating element 9. The connection between the container body 20 and the bottom plate 21 is as shown in FIG. As shown, press the bottom plate 21 with a presser jig.
By setting the rising angle of the inclined wall 22 to be more β than α, the outer diameter d is increased, and the outer diameter d of the inclined wall 23 is brought into close contact with the inner surface of the container body 20. At this time, the lower end surface of the container body 20 is made to protrude slightly x from the inclined wall 23. When the welding torch 24 is positioned at this fitting part and an arc is generated, the x part of the protruding part of the container body 20 melts, and the sloping wall 24 of the bottom plate 21 melts.
The outer periphery is also melted and welded to the base metal as shown in Figure 5. The wall thickness y of the welded portion 25 is formed so that the material of the protruding portion x of the container body 20 flows and is thicker than the plate thickness of other portions.

Therefore, there is no gap formed on the inner surface of the container 5 which causes 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 on the container body 20, it is easy to set it because D>d, and the work efficiency is extremely good because the inclined wall serves as a guide.

Furthermore, as shown in Fig. 4, during welding, the slanted wall 23 of the bottom plate 21 is held down by the holding jig A, so that it always comes into close contact with the inner surface of the container body 20 and lateral pressure is removed, so there is no poor fit and it is easy to reduce the wall thickness. It is.

In addition, since the parts other than the welding part are pressed and fixed by holding jig A, holding jig B, and 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 occurrence of fitting gaps. does not occur. Further, thermal deformation of the flat portion 22 of the bottom plate 21 and the mounting step portion 24 of the heating element 9 can be prevented. Therefore, the flat part 22 and the mounting step part 2
Since the thermal reed switch 11 and the heating element 9 are provided in close contact with each other, the temperature can be controlled reliably and with little variation.

Furthermore, as shown in FIG. 4, if a hole 26 for supplying an inert gas such as argon is provided in the holding jig C and the welding part 25 is filled with the welding part 25, an oxide film will be formed on the inner surface 25a of the welding part 25. is gone,
Surface treatments such as chemical polishing and electrolytic polishing are not required, resulting in lower costs. Particularly in this case, since the upper, lower and side surfaces of the inclined wall 23 of the bottom plate 20 and the container body 20 are cooled by a welding jig, the effect of preventing the formation of an oxide film is great. The plate materials of the container body 20 and bottom plate 21 are made of ultra-low carbon ferritic stainless steel containing 0.02% or less carbon and 15-20% chromium.
The use of a stainless steel plate containing molybdenum and 0.2 to 1.0% niobium or titanium has the effect that corrosion resistance does not deteriorate even when heated by welding.

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) As a single component, the outer diameter d of the inclined wall of the bottom plate is smaller than the inner diameter D of the container body, so it is easy to set up, and the inclined wall serves as a guide, making it extremely easy to work.

(2) During welding, the slanted wall of the bottom plate is held down by the holding jig A, so the outer diameter d of the slanted wall of the bottom plate is larger than the inner diameter D of the container body, ensuring close contact and lateral pressure, so there is no poor fit and welding is possible. becomes certain. Therefore, it becomes easy to reduce the wall thickness.

(3) Since the parts other than the welded parts are pressed and fixed by the holding jig A and the holding jig C, it is possible to restrict the heat from the welded parts from being conducted to other parts, and there will be no welding defects due to the occurrence of fitting gaps. . Further, thermal deformation of the flat part of the bottom plate and the mounting step part can be prevented, and since the thermal reed switch, heating element, etc. are provided in close contact with each other, the mounting is reliable and the temperature can be controlled with little variation.

(4) Since the parts other than the welded parts are pressed and fixed in a sealed state by holding jig A, holding jig B, and holding jig C,
If a hole is provided in the holding jig C to supply inert gas such as argon and the welding area is filled with air, an oxide film will not form on the inner surface of the welding area, and surface treatments such as chemical polishing and electrolytic polishing will no longer be required. Cost will be lower. 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 could cause corrosion, and the wall thickness is sufficient. The container has extremely high corrosion resistance without welding cracks.

(6) Since the welding between the container body and the bottom plate is performed at the outermost diameter, the parts can be left attached to the bottom and line organization is easy.

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

[Brief explanation of drawings]

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

Claims (1)

[Scope of Claims] 1. Consisting of a cylindrical container body and a plate bottom plate that is approximately dish-shaped and has a flat part and an inclined side wall, the inner diameter of the container body is D, and the outer diameter of the inclined wall of the bottom plate is d. When the bottom plate is inserted into the end face of the container body, D>d, and by reducing the slope of the inclined wall during welding, D<d is set, and this fitting part is welded to the base metal. Containers such as utensils. 2. A container such as a water heater as set forth in claim 1, wherein the lower end of the container body protrudes from and fits into the inclined wall, and the wall thickness of the melting portion is larger than the wall thickness of the container body.