JP6785586B2 - Hot water storage tank - Google Patents

Description

The present invention relates to savings hot water tank.

In recent years, hot water storage type water heaters have become widespread due to increasing awareness of energy conservation. Such a hot water storage type water heater has a metal hot water storage tank for storing boiling water, and inside the tank, a water flow called a baffle, which is near the hot water outlet or the water inlet, is provided. A plate-shaped structure for restraining is installed. Patent Document 1 discloses a heat pump type water heater provided with a hot water storage tank. In the hot water storage tank of Patent Document 1, a water inlet diffusion plate corresponding to a baffle is attached to a relatively low temperature region in the tank body of the hot water storage tank by spot welding. Further, Patent Document 2 discloses a baffle plate mounting structure in which a baffle plate used for a can body (tank body) of an electric water heater is welded to the end face of a water supply pipe instead of the can body.

Japanese Unexamined Patent Publication No. 2005-226858 (paragraphs 0044 to 0063, FIGS. 1, 2) Japanese Unexamined Patent Publication No. 2-203158 (page 2, upper right, line 5 to page 2, lower left, line 8, FIG. 1)

The baffle, which is a plate-shaped structure for suppressing the water flow near the hot water outlet or the water inlet, can be fixed to the tank can body by spot welding, which can be the simplest baffle mounting structure. The baffle mounting process is also short. However, when spot welding is performed, a narrow gap is generally generated around the joint portion joined by spot welding. For example, in a fully-filled stainless steel hot water storage tank, the passivation film on the surface of the stainless steel material is gradually destroyed by chloride ions in tap water, but the passivation is caused by the supply of oxygen from water except for narrow gaps. The coating is regenerated. However, since the oxygen required for the regeneration of the passivation film is insufficient in the narrow gap around the joint, gap corrosion occurs. As a result, crevice corrosion around the joint may progress, causing poor water leakage to the outside of the tank.

Therefore, in the heat pump type water heater of Patent Document 1, the baffle is spot-welded to the tank can body at a relatively low temperature position to improve the crevice corrosion resistance. However, since a narrow gap is generated in the vicinity of a general spot welded portion, the progress is slower than that of high-temperature water, but even low-temperature water causes crevice corrosion. The heat pump type water heater of Patent Document 1 performs spot welding in a limited manner in order to delay the progress of crevice corrosion that occurs at the joint due to spot welding, but for example, tap water containing chloride ions. Under such a corrosive atmosphere, crevice corrosion at the joint due to spot welding could not be sufficiently suppressed for a long period of time.

In Patent Document 2, by welding the baffle attachment to the end face of the water supply pipe instead of the tank can body, no hole is formed in the tank can body even if gap corrosion occurs, which is effective against poor water leakage. is there. However, since a gap is formed between the water supply pipe and the baffle, the gap corrosion itself cannot be suppressed.

The present invention solves the above-mentioned problems, and an object of the present invention is to provide a hot water storage tank that widens the gap near the welded portion between the materials to be welded during spot welding and suppresses the gap corrosion that occurs in a corrosive atmosphere. ..

The hot water storage tank of the present invention is provided with a metal tank can body having a dynamic coating on the surface, an introduction port for introducing water into the tank can body, and an outlet for drawing out hot water stored in the tank can body. Therefore, a metal baffle that suppresses the water flow when introducing water into the tank can body or when hot water is drawn out from the tank can body and has an immovable coating on the surface is provided around the introduction port inside the tank can body. Provided on either or both of the periphery of the outlet, the baffle comprises a baffle body, a baffle support leg that supports the baffle body, and a baffle support leg sole provided at the end of the baffle support leg. The concave portion formed on the bottom of the support leg is convex toward the tank can body side, is joined to the tank can body at the bottom of the concave portion, and the depth of the concave portion of the concave portion is determined by the baffle. By making the thickness equal to or greater than that of the above, a gap is formed between the bottom of the baffle support leg and the tank can body to facilitate the regeneration of the dynamic coating around the joint .

The hot water storage tank of the present invention can suppress crevice corrosion around the joint between the baffle support sole and the tank can body, and can prolong the life of the hot water storage tank.

It is explanatory drawing explaining the spot welding method by Embodiment 1 of this invention. It is a figure which shows the joint part formed by performing the spot welding method by Embodiment 1 of this invention. It is a front view of the 1st electrode according to Embodiment 1 of this invention. It is a front view of another first electrode according to Embodiment 1 of this invention. It is a front view of another first electrode according to Embodiment 1 of this invention. It is a front view of another first electrode according to Embodiment 1 of this invention. It is a front view of another first electrode according to Embodiment 1 of this invention. It is sectional drawing of the concave part of the first welded material according to Embodiment 1 of this invention. It is explanatory drawing explaining the spot welding method by the comparative example. It is a front view of the hot water storage tank according to Embodiment 2 of this invention. It is a top view of the baffle attached to the hot water storage tank of FIG. It is explanatory drawing of the spot welding of the baffle in the hot water storage tank of FIG. It is a figure which shows the joint part of the baffle in the hot water storage tank of FIG.

Embodiment 1.
FIG. 1 is an explanatory view for explaining the spot welding method according to the first embodiment of the present invention, and FIG. 2 is a diagram showing a joint formed by executing the spot welding method according to the first embodiment of the present invention. The spot welding method is a step of applying an electric current while crimping two materials 13 and 14 to be welded by two electrodes 11 and 12 and melting and joining the metals of the materials 13 and 14 to be welded by the resistance heat (welding process). Is a joining method to carry out. The joint portion 15 in which the two materials to be welded are joined by spot welding is a point-shaped joint portion called a nugget. The electrode described in the upper part of the figure is referred to as a first electrode 11, and the material to be welded on the side of the first electrode 11 is referred to as the first material to be welded 13. Further, the electrode described in the lower part of the drawing is referred to as a second electrode 12, and the material to be welded on the side of the second electrode 12 is referred to as a second material 14 to be welded. Further, the first welded material 13 is provided with a concave concave portion 16 on the first electrode 11 side, and the first welded material 13 and the second welded material 14 are in contact with each other at the concave portion 16. There is. Hereinafter, the first electrode 11 and the first material to be welded 13 will be installed on the upper side, the second electrode 12 and the second material to be welded 14 will be installed on the lower side, and spot welding will be performed. If they are the same, the top and bottom may be exchanged, and both electrodes 11 and 12 may be installed in the horizontal direction or in a direction oblique from horizontal. Further, the first electrode 11 has an end portion 11a at the tip that contacts the first material to be welded 13, and the second electrode 12 has an end portion 12a at the tip that contacts the second material to be welded 14.

The first electrode 11 shown in FIGS. 1 and 2 will be described with reference to FIGS. 3 to 7. Many shapes can be used for the first electrode 11.
The electrode 1 shown in FIG. 3 is an example of the first electrode 11, and the end portion 1a in contact with the first welded material 13, which is called a dome shape, is a spherical or hemispherical electrode. In carrying out the spot welding method of the first embodiment, it is desirable that the first electrode 11 has a tip diameter as small as possible, so that the radius of curvature is rather larger than that of a radius shape composed of a spherical surface having a large radius of curvature. A dome shape consisting of a small spherical surface is more suitable. The end portion 1a corresponds to the end portion 11a of the first electrode 11.

The electrode 2 shown in FIG. 4 is also an example of the first electrode 11, and is an electrode in which a circular plane-shaped central end portion 2b is formed at the central portion of a spherical or hemispherical end portion 2a. The electrode 2 can be used in the same manner, and the electrode 2 is shown in the example of the first electrode 11 in FIG. Further, as in the electrode 3 shown in FIG. 5, there is also an electrode in which a central end portion 3b having a spherical or hemispherical shape and a spherical surface having a radius of curvature larger than that of the end portion 3a is formed at the central portion of the end portion 3a. It can be used in the same way. Here, it is desirable that the diameters of the central end portions 2b and 3b formed on the end portions 2a and 3a of the electrodes 2 and 3 are close to the diameter of the joint portion 15 required for spot welding.

Further, the first electrode 11 may be an electrode 4 having a truncated cone shape at the end 4a, which is generally called a truncated cone shape as shown in FIG. 6, and is generally called a truncated cone radius shape as shown in FIG. An electrode 5 having a truncated cone radius shape at the end 5a may be used. The electrode 4 has a circular plane-shaped central end portion 4b formed at the central portion of the end portion 4a. The electrode 5 is formed with a central end portion 5b having a spherical surface having a radius of curvature larger than that of the end portion 5a at the central portion of the end portion 5a. Here, similarly to the electrodes 2 and 3, the diameters of the central end portions 4b and 5b formed at the end portions 4a and 5a of the electrodes 4 and 5 are also close to the diameter of the joint portion 15 required for spot welding. It is desirable to set it to a value.

As the other shape of the first electrode 11, although not shown in the figure, a point dome type or a point dome radius type electrode can also be used. Further, an electrode having a shape called a flat shape having the same electrode root diameter and tip diameter, or an electrode having an eccentric end shape from the electrodes shown so far may be used, but in the second embodiment. As will be described later, it is not desirable because it is relatively difficult to provide the concave portion 21d corresponding to the end shape of the electrode.

Next, the concave portion 16 formed on the first welded material 13 shown in FIGS. 1 and 2 will be described with reference to FIG. As for the concave portion 16, many shapes can be used as in the case of the first electrode 11, and the method for forming the concave portion 16 is not limited. The concave portion 16 shown in FIG. 8 is an example of the concave portion 16 shown in FIGS. 1 and 2, and has a circular table shape formed from a flat bottom portion 16a and an inclined portion 16b. Here, the diameter of the flat bottom portion 16a is slightly larger than the diameter of the joint portion 15 required for spot welding, preferably about 1 to 2 mm larger. In other words, when the first electrode 11 is a plane or an electrode having a spherical surface different from the end shape is used for the central ends 2b, 3b, 4b, and 5b of the electrodes as shown in FIGS. 2 to 5, the plane bottom portion 16a The diameter of the first electrode 11 is slightly larger than the diameter of the central end portion 11b of the first electrode 11 (for example, the diameter of the central end portion 2b of the electrode 2), preferably about 1 to 2 mm larger.
The depth 16c of the concave shape 16 is not particularly limited, but it is at least 0.1 mm or more, and if possible, it is preferably about the plate thickness of the first welded material 13. Further, the diameter of the opening 16d of the concave portion 16 may be large enough not to interfere when the first electrode 11 comes into contact with the flat bottom portion 16a of the concave portion 16. That is, it is desirable to determine by the diameter and end shape of the first electrode 11 to be used.

In FIG. 8, the concave portion 16 has been described as having a circular shape, but the flat bottom portion 16a and the inclined portion 16b may have a curved shape, and the flat bottom portion 16a and the inclined portion 16b may have an integrated curved shape. It may be present, and it is desirable to optimize it according to the diameter and end shape of the first electrode 11 to be used. However, the flat bottom 16a is preferably a flat surface, and even if it is a curved surface, the radius of curvature is preferably as large as possible. Even when the flat bottom portion 16a is a curved surface, it is most desirable that the diameter of the curved surface portion is about 1 to 2 mm larger than the diameter of the central end portion 11b of the first electrode 11.

Next, the second electrode 12 shown in FIGS. 1 and 2 will be described. As the second electrode 12, many shapes can be used as in the first electrode 11, and all the shapes shown as the shape examples of the first electrode 11 above can be used. However, it is most desirable that the end of the second electrode 12 is flat, and if it is not flat, it is desirable that the second electrode 12 has a curved surface having a radius of curvature as large as possible. Further, it is also desirable that the second electrode 12 has a shape called a flat shape having the same electrode root diameter and tip diameter. As will be described later, when the concave portion 16 is also provided on the second welded material 14, it is desirable that the second electrode 11 has the same shape as the first electrode 11.
Further, it is desirable that the end diameter of the second electrode 12 is the same as or larger than the end diameter of the first electrode 11. However, as will be described later, when the second welded material 14 is also provided with a concave portion, it is most desirable that the diameter is the same as the end diameter of the first electrode 11.
Regarding the second material to be welded 14, it is not always necessary to provide the concave portion 16 as shown in FIGS. 1 and 2, but the concave portion 16 may be provided as in the first material 13 to be welded. In that case, it is desirable that the shape is the same as that of the first welded material 13, but a different shape may be used.
As the electrode material of the first electrode 11 and the second electrode 12, general electrode materials for spot welding such as copper, chromium copper, beryllium copper, and zirconium copper may be used. However, the electrode materials of the first electrode 11 and the second electrode 12 must be materials having a higher thermal conductivity than the materials to be welded (the first material to be welded 13 and the second material to be welded 14). Further, the first electrode 11 and the second electrode 12 may be an integral type electrode or a cap type electrode.

The spot welding method according to the first embodiment of the present invention will be described in comparison with the comparative example of FIG. FIG. 1 shows a state before passing an electric current through the first electrode 11 and the second electrode 12 in the spot welding method of the first embodiment, and FIG. 2 shows a joint portion after the spot welding method of the first embodiment is performed. It shows the surrounding condition.
In addition, FIG. 9 shows the state around the joint after performing the spot welding method of the comparative example, which is a general spot welding method. In the spot welding of the comparative example of FIG. 9, the first electrode 31 having the end portion 31a formed with the central end portion 31b in contact with the first material to be welded 33 and the central end portion in contact with the second material to be welded 34 It has a second electrode 32 having an end portion 32a on which 32b is formed, and the shapes of the end portion 31a and the central end portion 32b of the first electrode 31 and the end portion 32a and the central end portion 32b of the second electrode 32 are In general, they are often the same. In the spot welding method of the comparative example as shown in FIG. 9, the first material to be welded 33 and the second material to be welded 34 are not extremely deformed during welding, and a narrow gap 37 is formed around the joint portion 35. Welded.

On the other hand, in the spot welding method of the first embodiment shown in FIGS. 1 and 2, the first workpiece 13 is provided with a concave portion 16, and the flat bottom portion 16a of the concave portion 16 is formed. It is about 1 to 2 millimeters larger than the diameter of the central end portion 11b applied to the end portion 11a of the first electrode 11 to be used. When the portion of the concave portion 16 is welded when the first material to be welded 13 and the second material to be welded 14 are welded, the diameter of the central end portion 11b applied to the end portion 11a of the first electrode 11 after welding. A joint portion 15 having a diameter close to is formed. Here, as described above, the diameter of the flat bottom portion 16a of the concave portion 16 is larger (preferably about 1 to 2 mm) with respect to the diameter of the joint portion 15. Therefore, the length of the narrow gap 17 generated around the joint portion 15 is at most the diameter obtained by subtracting the diameter of the joint portion 15 from the diameter of the flat bottom portion 16a of the concave shape portion 16. Further, in the portion beyond the narrow gap 17 seen from the joint portion 15, a gap 18 larger than that of the spot welding method of the comparative example corresponding to the conventional spot welding method is generated.

The product in which the spot welding method of the first embodiment is applied to the first welded material 13 and the second welded material 14 of stainless steel, and the spot welding method of the comparative example similar to the conventional one is the first welded material of stainless steel. Consider a case where the products applied to the welded material 33 and the second welded material 34 are placed in an atmosphere containing chloride ions, that is, in a corrosive atmosphere.
Generally, crevice corrosion is said to occur when a crevice with a width of 30 to 40 micrometers or less exists with a length of about 2 mm or more. Therefore, as shown in the comparative example of FIG. 5, the product in which the spot welding method of the comparative example similar to the conventional one is applied to the first welded material 33 and the second welded material 34 of stainless steel is a joint portion. Since a narrow gap 37 of several micrometer to several tens of micrometer or less is generated around 35, the passivation film is locally destroyed by chloride ions, which is necessary for the fractured portion to be regenerated. The supply of oxygen cannot keep up, the passivation film is lost from the surface of the stainless steel, and finally crevice corrosion occurs.

On the other hand, in the case of the spot welding method of the first embodiment, the difference between the diameter of the central end portion 11b applied to the end portion 11a of the first electrode 11 and the diameter of the flat bottom portion 16a of the concave portion 16 is 1-2. If it is in millimeters, the length of the narrow gap 17 generated around the joint portion 15 is 1 to 2 mm or less, and a large gap 18 is further formed around the joint portion 15. Therefore, even if the surface of the passivation film on the surface of the stainless steel is slightly destroyed, oxygen is sufficiently supplied to the narrow gap 17 around the joint portion 15, and the passivation film is rapidly regenerated. The passivation film is not chipped from the stainless steel surface. Therefore, in the product welded by the spot welding method of the first embodiment, the passivation film is less likely to be destroyed even in the narrow gap 17 around the joint portion 15, and the gap corrosion can be suppressed. The passivation film in stainless steel is an oxide film of chromium.

An example of using stainless steel for the two materials to be welded (first material to be welded 13 and second material to be welded 14) has been shown, but materials such as aluminum alloys and titanium alloys that form a passivation film may be used. The same effect can be obtained by using these materials, and these materials may be used in combination. The passivation film in an aluminum alloy is an oxide film of aluminum, and the passivation film in a titanium alloy is an oxide film of titanium. Further, it is desirable that the two materials to be welded (first material to be welded 13 and second material to be welded 14) have a plate thickness within a range in which general spot welding is possible, and the two materials to be welded. When there is a difference in plate thickness between the materials (first material to be welded 13 and second material to be welded 14), either of them may be used as the first material to be welded 13.

As described above, in the spot welding method of the first embodiment, the length of the narrow gap between the materials to be welded around the joint is shortened, and a large gap is formed around the gap, so that the atmosphere is corrosive. It is possible to suppress crevice corrosion caused by local destruction of the passivation film in a narrow gap between certain materials to be welded.

Embodiment 2.
The second embodiment shows an example of a metal hot water storage tank manufactured by using the spot welding method of the first embodiment. FIG. 10 is a front view showing a hot water storage tank according to a second embodiment of the present invention, and FIG. 11 is a plan view showing a baffle of FIG. FIG. 12 is an explanatory view showing a spot welding method of the baffle in the hot water storage tank of FIG. 10, and FIG. 13 is a view showing a joint portion of the baffle in the hot water storage tank of FIG. The hot water storage tank 50 includes a tank can body 22, a water introduction port 23 for introducing water into the hot water storage tank 50, a hot water outlet 24 for leading out hot water stored in the hot water storage tank 50 to the outside, and a vicinity of the water introduction port 23. And baffles 21 provided around the hot water outlet 24 are provided. The baffle 21 is a plate-shaped structure, and has an effect of suppressing the water flow in the vicinity of the hot water outlet or the water inlet inside the tank can body 22. FIG. 10 shows an example in which the water introduction port 23 is provided in the lower part of the tank can body 22 and the hot water outlet 24 is provided in the upper part of the tank can body 22. The baffle 21 provided around the water introduction port 23 suppresses the flow of water flowing in from the water introduction port 23. The baffle 21 provided around the hot water outlet 24 suppresses the flow of hot water flowing out from the inside of the hot water storage tank 50 to the hot water outlet 24.

The baffle 21 shown in FIG. 11 includes a flat plate-shaped baffle body 21a having a hole 21e in the center, a plurality of baffle support legs 21b for supporting the baffle body 21a, and a baffle support leg bottom 21c. Further, the baffle support leg bottom 21c is provided with a concave portion 21d, which is an example of the concave portion 16 described in the first embodiment, and is in contact with the concave portion 21d on the tank can body 22 side. The concave portion 21d is preferably applied to the central portion of the baffle support leg bottom 21c, but if the first electrode 11 and the baffle support leg 21b come into contact with each other during spot welding, the concave portion 21d may be provided so as to be offset from the central portion.

In carrying out the spot welding method of the first embodiment on the hot water storage tank 50, the presence or absence and position of the hole 21e in the baffle body 21a of the baffle 21, and the number of the baffle support legs 21b and the baffle support leg bottom 21c are not limited, but at least the tank can It is desirable that the structure has a baffle support leg bottom 21c and a concave portion 21d, which are joint portions for joining the body 22 and the baffle 21 by spot welding. Further, FIG. 11 shows a baffle 21 having four baffle support legs 21b and a baffle support leg bottom 21c.
Further, the baffle 21 is generally made of metal, and is often made of the same material as the hot water storage tank 50. The baffle 21 and the tank can body 22 of the hot water storage tank 50 of FIG. 13 will be described as being made of stainless steel, but materials such as an aluminum alloy and a titanium alloy forming a passivation film may be used, and these materials may be used. May be used in combination. Baffle 21
The plate thickness of the tank can body 22 may be about the same as that of the tank can body 22, and it is desirable to manufacture a tank can body 22 having the same plate thickness from the viewpoint of effective use of resources. ..

FIG. 12 shows a state before welding when the baffle support leg bottom 21c is attached to the tank can body 22 by using the spot welding method of the first embodiment. In FIG. 12, the electrode 2 described in FIG. 4 is used as an example of the first electrode 11 and the second electrode 12. However, the present invention is not limited to this example, and any electrode having the characteristics described in the first embodiment can be used as the first electrode 11, and the second electrode 12 can also be used. An electrode having another shape can be used as the second electrode 12 as long as the electrode has the characteristics described in the first embodiment. Further, as the electrode material of the first electrode 11 and the second electrode 12, general electrode materials for spot welding such as copper, chromium copper, beryllium copper, and zirconium copper may be used. However, it must be a material with a higher thermal conductivity than the material to be welded (tank body 22, baffle support sole 21c). Further, the first electrode 11 and the second electrode 12 may be an integral electrode or a cap electrode.

The target positions of the first electrode 11 and the second electrode 12 are aligned with the bottom of the concave portion 21d provided on the baffle support leg bottom 21c. Here, the baffle support leg bottom 21c is used as the material to be welded on the first electrode 11 side, and the tank can body 22 is used as the material to be welded on the second electrode 12 side. It is possible to replace the material to be welded or to provide a concave portion on the tank can body 22, but this is not desirable due to the structure and function of the tank. Further, in order to reduce the deformation of the tank can body 22, an electrode having a flat center end 12b of the second electrode 12 or an electrode having a radius of curvature at the end of the tip spherical surface as large as possible was used. Better.

FIG. 13 shows a state after spot welding of the first embodiment to the concave portion 21d and the tank can body 22 provided on the baffle support leg bottom 21c in the second embodiment of the present invention. The concave portion 21d provided on the baffle support leg bottom 21c is larger than the diameter of the central end portion 11b provided on the end portion 11a of the first electrode 11 to be used, as in the flat bottom portion 16a of the concave portion 16 of the first embodiment. It is about 1 to 2 millimeters larger. Therefore, after welding the concave shape 21d applied to the baffle support leg bottom 21c and the tank can body 22, a joint portion 25 having a diameter close to the diameter of the central end portion 11b applied to the end portion 11a of the first electrode 11 is formed. However, the diameter of the bottom of the concave portion 21d is larger (preferably about 1 to 2 mm) with respect to the diameter of the joint portion 25. Therefore, the length of the narrow gap 27 generated around the joint portion 25 is at most the diameter obtained by subtracting the diameter of the joint portion 25 from the diameter of the bottom portion of the concave portion 21d. Further, in the portion beyond the narrow gap 27 seen from the joint portion 25, a gap 28 larger than that of the spot welding method of the comparative example corresponding to the conventional spot welding method is generated.

In the case of the hot water storage tank 50 in which a large gap 28 is opened around the joint portion 25 by spot welding in this way, even if the inside is filled with tap water, the hot water storage tank 50 formed inside the hot water storage tank 50 by chloride ions. Even if the surface of the passivation film is slightly destroyed, oxygen is sufficiently supplied to the narrow gap 27 around the joint 25, the passivation film is rapidly regenerated (repaired), and the passivation film is tanked. There is no loss from the metal (stainless steel, etc.) surface of the can body 22.
Therefore, in the hot water storage tank 50 of the second embodiment welded (joined) by the spot welding method of the first embodiment, the passivation film is less likely to be destroyed even in the narrow gap 27 around the joint portion 25, and the gap corrosion Can be suppressed.

As described above, according to the present invention, unlike the heat pump type water heater of Patent Document 1, the hot water storage tank 50 of the second embodiment, that is, the hot water storage tank 50 using the spot welding method of the first embodiment, has a joint portion 25. Since a narrow gap 27 and a large gap 28 having a maximum length of 2 mm or less are formed around the surface, gap corrosion can be suppressed even in a high temperature portion. Therefore, in the hot water storage tank 50 of the second embodiment, the baffle mounting structure can be unified to spot welding regardless of whether it is a high temperature portion or a low temperature portion, so that the tank structure can be simplified. Further, in a hot water storage tank using a conventional spot welding method in which a narrow gap is formed around a joint portion, gap corrosion progresses even in a low temperature portion. However, in the hot water storage tank 50 of the second embodiment using the spot welding method of the first embodiment, it is possible to suppress the crevice corrosion that progresses even in a low temperature portion in the hot water storage tank using the conventional spot welding method. Therefore, poor water leakage from the tank can body 22 can be suppressed, and the tank life can be extended.

Further, in the baffle plate mounting structure of Patent Document 2, water leakage failure from the tank can body is prevented by welding the baffle mounting to the end face of the water supply pipe instead of the tank can body, but the mounting structure is complicated. There is. However, in the hot water storage tank 50 of the second embodiment using the spot welding method of the first embodiment, water leakage failure can be suppressed without adopting a structure like the baffle plate mounting structure of Patent Document 2, so that the tank structure can be used. It can be simplified. Further, in the baffle plate mounting structure of Patent Document 2, since the water supply pipe and the baffle are welded by using a conventional spot welding method, a narrow gap is generated around the joint portion, and the gap corrosion itself cannot be suppressed. .. However, in the hot water storage tank 50 of the second embodiment using the spot welding method of the first embodiment, crevice corrosion is suppressed and the tank quality is improved.

Up to this point, an example of joining a baffle to the inside of a metal hot water storage tank by spot welding has been described, but the same effect can be obtained by using spot welding of the first embodiment to other parts of the hot water storage tank. .. Further, the spot welding method of the first embodiment is not limited to the hot water storage tank, and can be applied to joining a structure made of stainless steel or the like used in a corrosive atmosphere. For example, even if spot welding of the first embodiment is performed on an internal structure such as a stainless steel fuel tank or a refueling pipe, the life is extended by suppressing crevice corrosion and the structure is simplified by using spot welding. it can. Although stainless steel has been used as the two materials to be welded (first material to be welded 13 and second material to be welded 14), materials such as aluminum alloys and titanium alloys that form a passivation film may be used. The same effect can be obtained by using these materials, and these materials may be used in combination.

In the present invention, the contents of each embodiment can be freely combined, and each embodiment can be appropriately modified or omitted within a consistent range.

1, 2, 3, 4, 5: Electrodes, 1a, 2a, 3a, 4a, 5a, 11a, 31a, 32a: Ends, 2b, 3b, 4b, 5b, 11b, 31b, 32b: Central ends, 11 , 31: 1st electrode, 12, 32: 2nd electrode, 13, 33: 1st welded material, 14, 34: 2nd welded material 15, 35: joint (nugget), 16, 21d: concave shape Part, 16a: Flat bottom, 16b: Inclined, 16c: Concave depth, 16d: Opening, 17, 37, 27: Narrow gap, 18: Large gap, 21: Baffle, 21a: Baffle body, 21b : Baffle support leg, 21c: Baffle support leg bottom, 21e: Hole, 22: Tank can body, 23: Water inlet, 24: Hot water outlet, 50: Hot water storage tank

Claims (2)

A hot water storage tank equipped with a metal tank can body having a passivation coating on the surface, an introduction port for introducing water into the tank can body, and an outlet for drawing out hot water stored in the tank can body from the tank can body. There,
A metal baffle that suppresses the water flow when introducing water into the tank can body or when hot water is drawn out from the tank can body and has an immobile coating on the surface of the introduction port inside the tank can body. The baffle is provided on the periphery, the periphery of the outlet, or both, and the baffle is provided on the baffle body, the baffle support leg that supports the baffle body, and the baffle provided at the end of the baffle support leg. The concave portion provided with the support leg bottom and formed on the baffle support leg bottom is convex toward the tank can body side, and is joined to the tank can body at the bottom of the concave shape portion. By setting the depth of the recess to be equal to or greater than the thickness of the baffle, a gap is formed between the baffle support leg bottom and the tank can body to facilitate the regeneration of the dynamic coating around the joint. A hot water storage tank characterized by being The hot water storage tank according to claim 1, wherein the plate thickness of the baffle is the same as the plate thickness of the tank body.

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