Electric water heater with a heat-fusion bonded water tank

Abstract

The present invention relates to an electric water heater having a heat-fusion bonded hot water tank. The electric water heater comprises: an upper hot water tank including a first body portion having an open bottom and a first dome portion forming the top of the first body portion; and a lower hot water tank including a second body portion having an open top and a second dome portion forming the bottom of the second body portion, wherein the lower of the upper hot water tank and the upper of the lower hot water tank are heat-fusion bonded to form a hot water tank.

Description

Technology Field

[0001] The present invention relates to an electric water heater, and more specifically, to an electric water heater having a heat-fused water tank, wherein the upper water tank and the lower water tank are connected by a heat-fused bonding method to withstand internal expansion pressure. Background Technology

[0002] Generally, electric or gas boilers are installed to provide heating and hot water. However, installing a boiler solely for hot water use has the disadvantage of being uneconomical. Therefore, in cases where only hot water is required, a water heater designed exclusively for hot water production can be installed.

[0003] Water heaters are classified into electric types that use electricity as a heat source and combustion types that use gas. Electric water heaters are becoming more widely adopted because they offer the advantage of allowing for a free choice of installation location since they do not require an exhaust pipe, and they can be manufactured in a relatively compact size.

[0004] Meanwhile, water heaters are classified into instantaneous types, which produce hot water by heating it instantaneously upon use, and storage types, which produce and store hot water in advance. Instantaneous electric water heaters produce hot water by instantaneously heating flowing cold water using electric heating, and have the advantage of being usable immediately even without any pre-produced and stored hot water.

[0005] However, instantaneous electric water heaters have the disadvantage that the hot water temperature is highly variable depending on the water pressure or the flow rate of cold water.

[0006] Recently, the adoption of storage-type electric water heaters has been expanding to compensate for the shortcomings of instantaneous water heaters. These models are more economical, consume relatively less electricity, and offer lower costs. Since storage-type electric water heaters require a certain amount of time to heat cold water to a desired temperature, it is common practice to heat the stored water using an electric heater to ensure it is always maintained at a set temperature.

[0007] In order to use hot water in a storage-type electric water heater, a hot water tank is absolutely necessary to heat and store the water at a set temperature. However, expansion pressure is generated during the process in which cold water is heated to become hot water. Therefore, in a storage-type electric water heater, designing the hot water tank to withstand the overpressure caused by expansion pressure is one of the most important design issues.

[0008] Conventionally, metal hot water tanks were used to withstand expansion pressure, or plastic hot water tanks were housed within a metal housing to withstand overpressure. However, in this case, transportation is difficult due to the weight of the metal, and it is difficult to install them simply on side walls, etc.

[0009] To overcome the drawbacks of such storage-type electric water heaters, research is ongoing to use plastic as the material for the hot water tank. However, these plastic hot water tanks have the disadvantage of being relatively vulnerable to the expansion pressure caused by the generation of hot water.

[0010] To resolve the problems caused by such expansion pressure, the inventors of the present invention have proposed a method in Korean Registered Patent No. 10-2059266 to protect a hot water tank from expansion pressure formed inside the tank by providing an expansion pressure buffer formed of a diaphragm and a spring device. However, the expansion pressure buffer may lead to increased costs and an increase in the weight of the hot water tank.

[0011] There is a need for a method to manufacture a structurally stable hot water tank capable of withstanding expansion pressure without the need for a separate expansion pressure buffer. This can contribute to reducing installation and maintenance costs for electric water heaters, minimizing space constraints, and improving the overall energy efficiency of the water heater. Prior art literature

[0012] Korean Registered Patent No. 10-2059266 (Published on Feb. 11, 2020) The problem to be solved

[0013] The present invention aims to provide an electric water heater having a heat-fusion bonded hot water tank formed by joining an upper hot water tank and a lower hot water tank by heat fusion.

[0014] In addition, the present invention aims to provide an electric water heater comprising a hot water tank having durability capable of withstanding the expansion pressure of hot water without the need for a separate expansion pressure buffer, such as a diaphragm or a spring device. means of solving the problem

[0015] The present invention, for solving the above problems, relates to an electric water heater having a heat-fusion bonded hot water tank. The electric water heater comprises an upper hot water tank including a first body portion with an open bottom and a first dome portion forming the top of the first body portion; and a lower hot water tank including a second body portion with an open top and a second dome portion forming the bottom of the second body portion, and may include a hot water tank formed by heat-fusion bonding the bottom of the upper hot water tank and the top of the lower hot water tank.

[0016] According to an embodiment of the present invention, a first coupling part in the form of a flange protruding outward is formed at the bottom of the upper hot water tank, and a second coupling part in the form of a flange protruding outward is formed at the top of the lower hot water tank, and a heat-fused part in the form of a reinforcing flange protruding outward can be formed by heat-fusion of the first coupling part and the second coupling part.

[0017] According to an embodiment of the present invention, the first body portion of the upper hot water tank may include a plurality of stepped portions in which the outer surface is steppedly reduced toward the first dome portion and a step portion between the stepped portions, or the second body portion of the lower hot water tank may include a plurality of stepped portions in which the outer surface is steppedly reduced toward the second dome portion and a step portion between the stepped portions.

[0018] According to an embodiment of the present invention, a heater mounting portion is formed in the second dome portion of the lower hot water tank to which a heater is inserted and mounted, a cold water inlet pipe for introducing cold water into the hot water tank, and a hot water outlet pipe for discharging hot water inside the hot water tank to the outside may be formed to extend downward.

[0019] According to an embodiment of the present invention, a lower pipe is formed inside the lower hot water tank, the lower end of which is connected to a second dome portion and extends to a position corresponding to the second coupling portion, and an upper pipe is formed inside the upper hot water tank, the upper end of which is connected to a first dome portion and extends to a position corresponding to the first coupling portion. The upper pipe and the lower pipe are fused together when the upper hot water tank and the lower hot water tank are heat-fused to form an internal hot water discharge pipe that connects the interior of the hot water tank in the height direction and forms a path for discharging hot water. An outlet hole for discharging hot water inside the hot water tank may be formed at the upper end of the upper pipe.

[0020] According to an embodiment of the present invention, the first dome portion of the upper hot water tank is provided with an alignment rod positioned on the outside side in parallel with the upper pipe, and the alignment rod and the hot water discharge pipe can serve as a reference for alignment when the upper hot water tank and the lower hot water tank are heat-fused.

[0021] According to an embodiment of the present invention, the hot water discharge pipe comprises: an external hot water discharge pipe extending to the lower part of the lower hot water tank; and an internal hot water discharge pipe formed as a pipe inserted into the interior of the hot water tank through the external hot water discharge pipe, which serves as a path for the hot water inside the hot water tank. Here, the pipe forming the internal hot water discharge pipe may be positioned so that its upper end contacts the first dome portion of the upper hot water tank and its lower end is supported by a hot water discharge pipe coupler connected through the external hot water discharge pipe.

[0022] According to an embodiment of the present invention, a reinforcing band made of metal material is installed on the stepped portion of the hot water tank so as to restrain the outer surface of the hot water tank against expansion pressure.

[0023] According to an embodiment of the present invention, the invention includes a case that accommodates the hot water tank inside, wherein the case includes a lower support portion to which a cold water inlet pipe coupler and a hot water outlet pipe coupler are coupled, a rear support portion fixed to a wall, and a cover portion covering the front, and a side support portion that supports the load of the hot water tank by engaging with the heat-fusion portion of the hot water tank may be fixed to the rear support portion.

[0024] According to an embodiment of the present invention, a fixing rod is formed protruding from the upper surface of the hot water tank, and a connecting member may be provided on the rear support portion of the case to be coupled to the fixing rod and to support the hot water tank toward the rear support portion.

[0025] According to an embodiment of the present invention, the upper hot water tank comprises a first body portion with an open bottom and a first dome portion forming the top of the first body portion; and the lower hot water tank comprises a second body portion with an open top and a second dome portion forming the bottom of the second body portion, wherein the bottom of the upper hot water tank and the top of the lower hot water tank may be formed by heat fusion bonding. Effects of the invention

[0026] According to the present invention, high durability and reliability are provided by forming a hot water tank by joining an upper hot water tank and a lower hot water tank using a thermal fusion method. Due to the thermal fusion joining, the upper hot water tank and the lower hot water tank are firmly connected, increasing resistance to expansion pressure inside the hot water tank and preventing leakage.

[0027] Furthermore, even though plastic materials are used for the hot water tank, the tank can be lightweighted by joining them via heat fusion to withstand expansion pressure. As a result, the structural strength of the hot water tank is improved, and stability can be maintained even during long-term use.

[0028] In addition, the upper pipe of the upper hot water tank and the lower pipe of the lower hot water tank are formed integrally during the manufacturing of the upper and lower hot water tanks, and are aligned upon heat fusion to form an integral internal hot water discharge pipe. Through this, the assembly process can be simplified.

[0029] Furthermore, the stepped and uneven sections formed on the outer surface of the hot water tank can further increase structural strength, thereby enhancing resistance to expansion pressure. Additionally, metal reinforcing bands can improve the pressure resistance of the hot water tank and prevent deformation.

[0030] In addition, the load of the hot water tank is distributed through the side supports and connecting members, maintaining the structural strength of the case and enabling stable support even with a lightweight structure. Brief explanation of the drawing

[0031] FIG. 1 is a front perspective view of an electric water heater according to the present invention. FIG. 2 is a side view of an electric water heater according to the present invention. FIG. 3 is a bottom view of an electric water heater according to the present invention. FIG. 4 is a drawing illustrating the upper hot water tank of a hot water tank according to an embodiment of the present invention, where FIG. 4 (a) is a front view of the upper hot water tank and FIG. 4 (b) is a cross-sectional view of the upper hot water tank. FIG. 5(a) is a plan view of the first dome portion (1130) of the upper hot water tank (1100), and FIG. 5(b) is a bottom view of the upper hot water tank (1100). FIG. 6 is a drawing illustrating a lower hot water tank of a hot water tank according to an embodiment of the present invention, where FIG. 6 (a) is a front view of the lower hot water tank and FIG. 6 (b) is a right side view of the lower hot water tank. FIG. 7 is a cross-sectional view of a lower hot water tank according to the present invention. FIG. 8 is a bottom view of the lower hot water tank of the hot water tank according to the present invention. FIG. 9 is a side view illustrating a reinforcement structure by a reinforcing band of a hot water tank according to an embodiment of the present invention. Specific details for implementing the invention

[0032] Hereinafter, specific details for implementing the present invention will be described with reference to the attached drawings. Furthermore, in describing the present invention, detailed descriptions of related known functions are omitted if they are deemed obvious to a person skilled in the art and could unnecessarily obscure the essence of the invention.

[0033] FIG. 1 is a front perspective view of an electric water heater according to the present invention, FIG. 2 is a side perspective view of an electric water heater according to the present invention,

[0034] Referring to FIGS. 1 and 2, the electric water heater according to the present invention includes a hot water tank (1000), a heater (2000), and a case (3000).

[0035] A hot water tank (1000) according to an embodiment of the present invention includes an upper hot water tank (1100) and a lower hot water tank (1200).

[0036] The upper hot water tank (1100) is formed in a semi-cylindrical shape with the top closed. The lower hot water tank (1200) is formed in a semi-cylindrical shape with the bottom closed, includes a cold water inlet pipe (1600) and a hot water outlet pipe (1700) extending downward, and is formed to allow a heater (2000) to be connected.

[0037] The hot water tank (1000) includes a heat-fused portion (1300) formed by joining an upper hot water tank (1100) and a lower hot water tank (1200) by heat fusion, and stores water in the internal space.

[0038] According to an embodiment of the present invention, the upper hot water tank (1100) and the lower hot water tank (1200) are formed with sizes corresponding to each other, and the heat fusion portion (1300) may be located in the middle of the height direction of the hot water tank (1000).

[0039] The heat fusion section (1300) integrally combines the upper hot water tank (1100) and the lower hot water tank (1200). The upper hot water tank (1100) and the lower hot water tank (1200) each include a first joining section (1310) and a second joining section (1320) for heat fusion (see FIG. 4), which will be explained in detail below.

[0040] The hot water discharge pipe (1700) can be divided into an external hot water discharge pipe (1700a) located on the lower surface of the hot water tank (1000) and an internal hot water discharge pipe (1700b) located inside the hot water tank (1000).

[0041] The internal hot water discharge pipe (1700b) is formed by extending the hot water discharge pipe (1700) into the interior of the hot water tank (1000). The internal hot water discharge pipe (1700b) is formed integrally with the hot water tank (1000) and extends in the height direction within the hot water tank (1000). The internal hot water discharge pipe (1700b) includes an upper pipe (1710) formed within the upper hot water tank (1100) and a lower pipe (1720) formed within the lower hot water tank (1200).

[0042] The upper pipe (1710) and the lower pipe (1720) are joined by heat fusion of the heat fusion section (1300) to form an internal hot water discharge pipe (1700b). The upper pipe (1710) and the lower pipe (1720) will be described in detail below with reference to FIGS. 4 and FIGS. 7.

[0043] The upper hot water tank (1100) includes a fixing rod (1132) in the center of the upper surface. The fixing rod (1132) is coupled to a connecting member (3200) to prevent the hot water tank (1100) from tilting, thereby allowing the load of the hot water tank (1000) to be supported by the case (3000).

[0044] The heater (2000) is coupled to the hot water tank (1000) and generates hot water inside the hot water tank (1000). The heater (2000) is mounted in a form in which a hot water sensor (2010) and an overheat detection sensor (2020) are integrally provided inside a spiral heating coil tube (2300) formed on the upper part of the heater housing (2200).

[0045] The heater (2000) operates while being controlled by a hot water sensor (2010) integrally provided with the heater (2000). The heater (2000) generates heat when the temperature of the water detected by the hot water sensor (2010) is lower than the temperature range set by the controller (4010), and turns off when the temperature of the water detected by the hot water sensor (2010) reaches the temperature range set by the controller (4010).

[0046] The overheat detection sensor (2020) is positioned in a manner that contacts the heating coil tube (2300). Therefore, if there is no water inside the hot water tank (1000) or the water is filled insufficiently, and the hot water sensor (2010) fails to accurately measure the temperature of the water, and heat generation by the heater (2000) continues, the overheat detection sensor (2020) detects this and turns off the heater (2000).

[0047] The overheat detection sensor (2020) is connected to a power control unit (4100) placed inside the case (3000) and prevents overheating by blocking the power supply to the heater (2000) through the control unit (4010).

[0048] The case (3000) contains and supports various parts of an electric water heater, including a hot water tank (1000), inside. The case (3000) includes a lower support portion (3110), a rear support portion (3120), and a cover portion (3150) that covers the front. The lower support portion (3110) and the rear support portion (3120) may be formed as L-shaped folded plates.

[0049] The rear support (3120) of the case (3000) is fixed to the wall at the electric water heater installation site.

[0050] A cold water inlet pipe coupler (4600) is coupled to the lower support member (3110) and connected to the cold water inlet pipe (1600), and a hot water outlet pipe coupler (4700) is coupled and connected to the hot water outlet pipe (1700). The lower portions of the cold water inlet pipe coupler (4600) and the hot water outlet pipe coupler (4700) are positioned to be exposed on the lower side of the lower support member (3110) and are connected to an external water pipe and a hot water pipe that supplies hot water to the user.

[0051] When water is filled inside the hot water tank (1000), a load including the weight of the water is formed in the hot water tank (1000). When the load formed by the hot water tank (1000) of the electric water heater is applied only to the lower surface of the case, the structural strength of the case must be greatly increased, and as a result, the load of the case increases.

[0052] In order to distribute the load of the hot water tank (1000), the electric water heater according to an embodiment of the present invention includes a side support member (3300) that supports the side of the hot water tank (1000). Through this, the load of the hot water tank (1000) is distributed to the rear support member (3120) of the case (3000) which is fixed to the wall.

[0053] In detail, as shown in the enlarged view of FIG. 2, the rear support portion (3120) of the case (3000) is provided with a side support portion (3300) that supports the load of the hot water tank (1000) by being caught on the heat-fused portion (1300) protruding to the side of the hot water tank (1000). Since the load of the hot water tank (1000) is distributed to the rear support portion (3120) of the case (3000) fixed to the wall surface by the side support portion (3300), the supporting force of the case (3000) supporting the hot water tank (1200) is strengthened.

[0054] Meanwhile, a connecting member (3200) is provided on the upper part of the case (3000) to fix the upper part of the hot water tank (1000) toward the rear support member (3120). One end of the connecting member (3200) is fixed to the rear support member (3120), and the other end is connected to the fixing rod (1132) at the top of the hot water tank (1000).

[0055] The fixed rod (1132) is formed in a shape that extends in the height direction of the upper hot water tank (1100) and can be formed together during the injection molding of the upper hot water tank (1100). One end of the connecting member (3200) is bent in an 'L' shape, and the bent part is fixed to the side of the rear support part (3120) of the case (3000).

[0056] The other end of the connecting member (3200) may be formed into a fixing hole (not shown) into which a fixing rod (1132) can be inserted and fixed. The connecting member (3200) prevents the hot water tank (1000) from tilting by pulling the hot water tank (1000) toward the rear support (3120) of the case (3000) and distributes the load of the hot water tank (1000) to the side support (3300).

[0057] The load of the hot water tank (1000) is distributed and supported by the lower support portion (3110) of the case (3000) combined with the cold water inlet pipe coupler (4600) and the hot water outlet pipe coupler (4700), and the rear support portion (3120) of the case (3000) combined with the side support portion (3300). Furthermore, a significant portion of the load is distributed and supported by the rear support portion (3120) which is fixed to the wall. Through this, even if the case (3000) is formed as a lightweight structure, the hot water tank (1000) filled with water can be stably supported.

[0058] FIG. 3 is a bottom view of an electric water heater according to the present invention.

[0059] Referring to FIGS. 1 to 3, a dial-shaped regulator (4010) is installed at the bottom of the cover portion (3150) and exposed to the outside. The regulator (4010) is electrically connected to a heater (2000). The heater (2000) heats the water inside the hot water tank (1000) to a set temperature by generating heat through a heating wire contained inside a spiral heating coil tube (2300).

[0060] A cold water inlet pipe coupler (4600) and a hot water outlet pipe coupler (4700) are coupled to the lower support portion (3110) of the case (3000). A controller (4010) is provided on the front of the case (3000) and configured to control the on / off of the heater (2000) and the temperature of the hot water generated inside the hot water tank (1000).

[0061] The hot water tank (1000) includes a safety valve (4200), and the safety valve (4200) protects the hot water tank (1000) by discharging water to the outside when overpressure is formed inside the hot water tank (1000).

[0062] The safety valve (4200) discharges water from inside the hot water tank (1000) to the outside when the pressure inside the hot water tank (1000) exceeds the set value, thereby preventing overpressure from forming inside the hot water tank (1000) that is greater than the set value.

[0063] The safety valve (4200) is configured to have a safety valve drain pipe (4220) (see FIG. 2) and a hose (not shown) connected to the safety valve drain pipe (4200) so that water inside the hot water tank (1000) can be forcibly discharged to the outside. The safety valve (4200) releases excessive pressure inside the hot water tank (1000) to prevent damage to the hot water tank (1000).

[0064] Hereinafter, the hot water tank (1000) of the electric water heater according to the present invention will be described in detail.

[0065] According to an embodiment of the present invention, a hot water tank (1000) is formed by joining an upper hot water tank (1100) and a lower hot water tank (1200), which are formed from a plastic material, by a heat fusion method.

[0066] According to an embodiment of the present invention, the upper hot water tank (1100) and the lower hot water tank (1200) are manufactured by injection molding using a plastic material.

[0067] FIG. 4 is a drawing illustrating the upper hot water tank of a hot water tank according to an embodiment of the present invention, where FIG. 4 (a) is a front view of the upper hot water tank and FIG. 4 (b) is a cross-sectional view of the upper hot water tank.

[0068] Referring to FIG. 4 (a) and (b), the upper hot water tank (1100) includes a first body portion (1120) and a first dome-shaped dome portion (1130) forming the top of the first body portion (1120). A first connecting portion (1310) for heat-fusion joining with the lower hot water tank (1200) is formed at the bottom of the first body portion (1120). The first connecting portion (1310) is formed in the shape of a flange protruding outward.

[0069] A first dome portion (1130) is formed at the top of the first body portion (1120), forming a structure in which the top of the upper hot water tank (1100) is closed. The bottom of the upper hot water tank (1100) forms an open portion that is connected to the lower hot water tank (1200).

[0070] The first body portion (1120) of the upper hot water tank (1100) can be formed in a shape in which the diameter of the cross-section gradually decreases toward the first dome portion (1130). At this time, the outer surface of the first body portion (1120) forms annular stepped portions (1400) and the diameter decreases stepwise.

[0071] A stepped portion (1410) is formed between the stepped portions (1400) formed on the outer surface of the first body portion (1120), and the stepped portion (1410) increases the cross-sectional rigidity of the upper hot water tank (1100). Accordingly, the hot water tank (1000) can secure resistance against the expansion pressure generated by the production of hot water inside the hot water tank (1000) while having reinforced cross-sectional rigidity.

[0072] A first coupling part (1310) for a heat-fusion part (1300) is formed at the bottom of the first body part (1120). A first fusion annular projection (1311) may be formed protruding annularly on the lower surface of the first coupling part (1310). The first fusion annular projection (1311) corresponds to the second fusion annular projection (1321) of the lower hot water tank (1200) shown in FIG. 6. The first fusion annular projection (1311) and the second fusion annular projection (1321) are melted by heat fusion to join and reinforce the first coupling part (1310) and the second coupling part (1320) to each other.

[0073] The upper tube (1710) is formed together with the upper hot water tank (1100) when injection molding. The upper end of the upper tube (1710) is connected to the first dome portion (1130) of the upper hot water tank (1100), and the lower end extends to the bottom of the first connecting portion (1310).

[0074] An outlet hole (1711) is formed adjacent to the top of the upper pipe (1710). The outlet hole (1711) can be formed through a cutting or drilling process, etc., after injection molding of the upper hot water tank (1100) and before joining with the lower hot water tank (1200).

[0075] When the upper hot water tank (1100) and the lower hot water tank (1200) are heat-fused, the upper pipe (1710) and the lower pipe (1720) (see FIG. 7) are fused together to form a single continuous passage. Through this, the external hot water discharge pipe (1700a) and the internal hot water discharge pipe (1700b) form a single hot water discharge passage, and the entire hot water discharge pipe (1700) is formed.

[0076] Meanwhile, since the upper pipe (1710) and the lower pipe (1720) are located inside the upper hot water tank (1100) and the lower hot water tank (1200), an alignment problem may occur during the heat fusion of the upper hot water tank (1100) and the lower hot water tank (1200).

[0077] To solve this, according to an embodiment of the present invention, an alignment rod (1133) may be provided on the upper part of the first dome portion (1130) of the upper hot water tank (1100) corresponding to the upper pipe (1710). The alignment rod (1133) may be formed together during injection molding of the upper hot water tank (1100) in a form that extends in the height direction of the upper hot water tank (1100). When heat-fused, by aligning the alignment rod (1133) and the lower pipe (1720) (see FIG. 7), the upper pipe (1710) and the lower pipe (1720) can form a single continuous passage.

[0078] FIG. 5(a) is a plan view of the first dome portion (1130) of the upper hot water tank (1100), and FIG. 5(b) is a bottom view of the upper hot water tank (1100).

[0079] Referring to FIG. 5, a first reinforcing rib (1131) is formed extending radially on the inner surface of the first dome portion (1130) of the upper hot water tank (1100). The first reinforcing rib (1131) extends radially along the radius of curvature from the center of the first dome portion (1130), and is formed to extend straight in the radial direction when projected onto a virtual plane.

[0080] The first reinforcing rib (1131) can increase the structural strength of the upper hot water tank (1100), particularly the first dome section (1130), while reducing the thickness of the hot water tank (1000). Accordingly, the first dome section (1130) can withstand the expansion pressure of the hot water inside the hot water tank (1000).

[0081] FIG. 6 is a drawing illustrating a lower hot water tank of a hot water tank according to an embodiment of the present invention, where FIG. 6 (a) is a front view of the lower hot water tank and FIG. 6 (b) is a right side view of the lower hot water tank.

[0082] Referring to FIG. 6, the lower hot water tank (1200) is formed to correspond to the upper hot water tank (1100) (see FIG. 4). The lower hot water tank (1200) includes a second body portion (1220) and a dome-shaped second dome portion (1230) forming the bottom of the second body portion (1220). A second connecting portion (1320) for heat-fusion joining with the upper hot water tank (1100) is formed at the top of the second body portion (1220). The second connecting portion (1320) is formed in the shape of a flange protruding outward.

[0083] The first joint (1310) and the second joint (1320) are joined by heat fusion, thereby forming a heat fusion portion (see FIG. 2). The heat fusion portion (1300) is formed in the shape of an annular reinforcing flange protruding outward from the outer surface of the hot water tank (1000).

[0084] A second coupling portion (1320) for a heat-fusion portion (1300) is formed on the upper part of the second body portion (1210). A second fusion annular projection (1321) may be formed annularly on the upper surface of the second coupling portion (1320).

[0085] After heat for fusion bonding is applied to the first joint (1310) and the second joint (1320), the first joint (1310) and the second joint (1320) are bonded integrally while in contact with each other. The first fusion annular projection (1311) and the second fusion annular projection (1321) flow between the first joint (1310) and the second joint (1320) by the force applied for bonding. Accordingly, the first joint (1310) and the second joint (1320) are bonded to each other and reinforced by the flowing material, so that a heat-fusion portion (1300) can be formed.

[0086] The heat-fused portion (1300) in the form of a reinforcing flange serves to reinforce the joint and middle portions of the hot water tank (1000). Accordingly, the heat-fused portion (1300) can provide sufficient resistance to pressure acting radially in the middle portion of the hot water tank (1000).

[0087] The second body portion (1220) of the lower hot water tank (1200) may be formed such that the diameter of the cross-section gradually decreases toward the second dome portion (1230). At this time, the outer surface of the second body portion (1220) forms annular stepped portions (1400) and the diameter decreases stepwise.

[0088] Similar to the first body part (1120), a stepped portion (1410) is formed between the stepped portions (1400) formed on the outer surface of the second body part (1210). The stepped portion (1410) increases the cross-sectional rigidity of the lower hot water tank (1200).

[0089] A safety valve mounting hole (1800) is formed on one side of the second dome portion (1230) of the lower hot water tank (1200), for example, on the second dome portion (1230) adjacent to the rear of the hot water tank (1200). A safety valve (4200) is installed in the safety valve mounting hole (1800). According to an embodiment of the present invention, a safety valve opening (1810) connected to the safety valve mounting hole (1800) is formed in the height direction. Therefore, the safety valve mounting hole (1800) can be formed together during the injection molding of the lower hot water tank (1200).

[0090] FIG. 7 is a cross-sectional view of a lower hot water tank according to the present invention. FIG. 8 is a bottom view of the lower hot water tank of the hot water tank according to the present invention.

[0091] Referring to FIGS. 7 and 8, a second dome section (1230) is formed at the bottom of the lower hot water tank (1200). A cold water inlet pipe (1600) and a lower pipe (1720) are formed extending downwards in the second dome section (1230), and a heater mounting section (1240) and a safety valve mounting hole (1800) may be formed.

[0092] The lower pipe (1720) is formed together with the lower hot water tank (1200) when injection molding. The upper end of the lower pipe (1720) extends to the upper end of the second connecting part (1320), and the lower end is connected to the second dome part (1230) of the lower hot water tank (1200). It is connected to the external hot water discharge pipe (1700a) at the second dome part (1230). When injection molding the lower hot water tank (1200), the lower pipe (1720) of the external hot water discharge pipe (1700a) and the internal hot water discharge pipe (1700b) are formed in a continuous form.

[0093] When heat-sealing, the alignment rod (1133) (see FIG. 4) and the lower pipe (1720) of the lower hot water tank (1200) can be heat-sealed while aligned with each other. Accordingly, the upper pipe (1710) and the lower pipe (1720) can be joined to form a continuous passage.

[0094] The upper tube (1710) and the lower tube (1720) form an integrated structure connected by heat fusion of the heat fusion part (1300).

[0095] Since each part of the external hot water discharge pipe (1700a) and the internal hot water discharge pipe (1700b) is formed together when the upper and lower hot water tanks (1100, 1200) are injection molded, additional work such as inserting a separate pipe-shaped hot water pipe to collect and discharge hot water inside the hot water tank (1000) is not required during the assembly process, thereby simplifying the manufacturing process.

[0096] However, the method of forming and the shape of the hot water discharge pipe (1700) are not limited thereto. For example, the hot water discharge pipe (1700) may be formed as an internal hot water discharge pipe formed by an external hot water discharge pipe (1700a) and a separate pipe for hot water (not shown) that is inserted and connected through the external hot water discharge pipe (1700a). In this case, the upper pipe (1710) is not formed during injection molding, and the lower pipe (1720) may be formed in a short shape to support the extension of the pipe inserted from the external hot water discharge pipe (1700a).

[0097] The pipe for the internal hot water discharge pipe is inserted through the external hot water discharge pipe (1700a) and can be formed with a length such that its upper end abuts the first dome portion (1130) of the upper hot water tank. In this case, the gap between the upper end of the pipe for the internal hot water discharge pipe and the first dome portion (1130) forms an outlet hole (1711), and hot water flows into the internal hot water discharge pipe.

[0098] At this time, the hot water discharge pipe coupler (4700) connected through the external hot water discharge pipe (1700a) can serve to fix the position of the lower end of the internal hot water discharge pipe. That is, the hot water discharge pipe (1700) can be formed by inserting the internal hot water discharge pipe without a separate process such as fusion.

[0099] A heater mounting portion (1240) for mounting a heater (2000) is formed in the center of the second dome portion (1230) of the lower hot water tank (1200). The heater mounting portion (1240) includes a through heater insertion hole (1242) into which the heater (2000) is inserted from the lower side to the upper side.

[0100] The heater mounting portion (1240) includes a first rim portion (1240a) surrounding the heater insertion hole (1242), a second rim portion (1240b) formed larger than the first rim portion (1240a) and positioned lower than the first rim portion (1240a), and a third rim portion (1240c) located lower than the second rim portion (1240b) and formed larger than the second rim portion (1230b). The third rim portion (1240c) is formed to protrude from the lower surface of the second dome portion (1230).

[0101] The first rim portion (1240a), the second rim portion (1240b), and / or the third rim portion (1240c) of the heater mounting portion (1240) prevent deformation of the heater mounting portion (1240) and improve the durability of the second dome portion (1230) on which the heater mounting portion (1240) is formed, thereby improving the resistance of the second dome portion (1230) to expansion pressure.

[0102] A fastening hole (1243) for fastening a heater (2000) is formed in the second rim portion (1240b). The fastening hole (1243) is located in the second rim portion (1240b), and the second rim portion (1240b) is formed in a shape having a column-shaped reinforcing rib (1243a) at the location of the fastening hole (1243).

[0103] The third rim portion (1230c) forms a rectangular storage space, and a heater plate (2100) (see FIG. 3) forming the lower surface of the heater (2000) is disposed within the storage space. After the heater (2000) is inserted from the bottom of the hot water tank (1000) through the heater insertion hole (1242), the heater plate (2100) forming the lower surface of the heater (2000) is disposed inside the third rim portion (1240c).

[0104] A fastening hole for bolt fastening is formed in the heater plate (2100), and a bolt is inserted through the fastening hole and fastened to a fastening hole (1243) formed in the second rim portion (1240b). At this time, the outer surface of the lower housing (2200) of the heater (2000) is fitted onto the inner surface of the first rim portion (1240a).

[0105] With the seal formed by the sealing structure formed by the lower housing (2200) and the heater plate (2100) of the heater (2000), the heater (2000) can be easily mounted on the heater mounting part (1240).

[0106] The inner surface of the second dome section (1230) includes a plurality of second reinforcing ribs (1231) that extend radially around the heater insertion hole (1242). The second reinforcing ribs (1231) increase the structural strength of the second dome section (1230).

[0107] According to an embodiment of the present invention, structural strength capable of withstanding expansion pressure acting in the vertical direction of the hot water tank is provided by the first reinforcing rib (1131) formed in the first dome portion (1130) of the upper hot water tank (1100) and the second reinforcing rib (1231) formed in the second dome portion (1230) of the lower hot water tank (1200), thereby preventing deformation and uniformly distributing internal pressure.

[0108] The lower hot water tank (1200) is equipped with a cold water inlet pipe (1600) and a hot water outlet pipe (1700).

[0109] The cold water inlet pipe (1600) extends downward in the height direction from the lower surface of the lower hot water tank (1200). A cold water supply hole (1610) is formed on the upper side of the cold water inlet pipe (1600) located inside the lower hot water tank (1200). According to an embodiment of the present invention, the cold water supply hole (1610) may be formed as a hole having a triangular cross-section that opens toward the inner surface of the lower hot water tank (1200) and widens toward the top.

[0110] Accordingly, water is supplied laterally around the heater (2000) inside the hot water tank (1000) through the cold water supply hole (1610), causing the water to flow spirally along the inner surface of the hot water tank (1000). As a result, the cold water supplied into the hot water tank (1000) fills the lower inner part of the hot water tank (1000) and fills in a manner that pushes the water inside the hot water tank (1000) upward.

[0111] A clamp mounting groove (1620) is formed at the bottom of the cold water inlet pipe (1600) that extends to the bottom of the hot water tank (1000). The clamp mounting groove (1620) is formed in the shape of an incision groove that cuts a portion of the cold water inlet pipe (1600) in the circumferential direction. Through this, the cold water inlet pipe coupler (4600) (see FIG. 1) coupled to the support portion (3110) of the case (3000) can be easily assembled. With the upper part of the cold water inlet pipe coupler (4600) inserted into the cold water inlet pipe (1600), the clamp can be inserted into the clamp mounting groove (1620) and fixed.

[0112] Meanwhile, a hot water discharge pipe (1700) is extended to the lower part of the hot water tank (1000) to discharge water heated by a heater (2000) to the outside. The hot water discharge pipe (1700) is extended symmetrically to the cold water inlet pipe (1600) with the heater mounting part (1240) in between.

[0113] A clamp mounting groove (1702) identical to the clamp mounting groove (1620) of the cold water inlet pipe (1600) may be formed in the lower part of the hot water discharge pipe (1700). The clamp mounting groove (1702) is formed in the shape of an incision groove that cuts a portion of the hot water discharge pipe (1700) in the circumferential direction. Through this, the hot water discharge pipe coupler (4700) (see FIG. 1) coupled to the lower support portion (3110) of the case (3000) can be easily assembled. With the upper part of the hot water discharge pipe coupler (4700) inserted into the inside of the hot water discharge pipe (1700), the clamp can be inserted into the clamp mounting groove (1702) and fixed.

[0114] FIG. 9 is a side view illustrating a reinforcement structure by a reinforcing band of a hot water tank according to an embodiment of the present invention. In FIG. 9, the lower hot water tank is omitted from the hot water tank.

[0115] Referring to FIG. 9, the hot water tank (1000) according to an embodiment of the present invention may further include a reinforcing band (1500) in the step portion (1400). The reinforcing band (1500) may be formed of a metal material. The reinforcing band (1500) can improve the pressure resistance of the hot water tank (1000) and prevent deformation of the hot water tank (1000) even after long-term use.

[0116] According to an embodiment of the present invention, the stepped portion (1400) structure formed on the outer surface of the hot water tank (1000) enables the installation of a reinforcing band (1500). The reinforcing band (1500) can be maintained without detaching from the hot water tank (1000) by the annular stepped portion (1400). The reinforcing band (1500) can be joined after the hot water tank (1000) is formed by heat-fusion of the upper hot water tank (1100) and the lower hot water tank (1200).

[0117] A reinforcing band (1500) is installed at least once on each of the stepped portions (1400) on the outer surface of the upper hot water tank (1100) and the lower hot water tank (1200) to provide pressure that restrains the expansion of the hot water tank (1000). That is, it provides a restraining force that opposes the expansion pressure of the hot water tank (1000). Through this, the internal pressure performance of the first body portion (1120) of the upper hot water tank (1100) and the second body portion (1130) of the lower hot water tank (1200) is improved.

[0118] The reinforcing band (1500) can be fixed by an assembly method at both ends, but is not limited to this and can be fixed by a method such as spot welding while the two ends are stacked.

[0119] The scope of protection in this field is not limited to the description and expression of the embodiments explicitly described above. Furthermore, it is added once again that the scope of protection of the present invention cannot be limited by obvious changes or substitutions in the technical field to which the present invention belongs. Explanation of the symbols

[0120] 1000: Hot water tank 1100: Upper hot water tank 1120: 1st body section 1130: 1st dome section 1132: Fixed rod 1133: Alignment rod 1200: Lower hot water tank 1220: Second body part 1230: 2nd dome section 1231: 2nd reinforcing rib 1240: Heater mounting section 1242: Heater insertion hole 1243: Fastening hole 1300: Thermal fusion part 1310: First joint 1311: First fused annular projection 1320: Second joint 1321: Second fused annular projection 1400: Stair section 1410: Step section 1500: Reinforcement band 1600: Cold water inlet pipe 1610: Cold water supply hole 1620: Clamp mounting groove 1700: Hot water drain pipe 1700a: External hot water drain pipe 1700b: Internal hot water drain pipe 1702: Clamp mounting groove 1710: Upper pipe 1711: Outlet 1720: Lower pipe 1800: Safety valve mounting hole 1810: Safety valve open 2000: Heater 2010: Hot water sensor 2020: Overheating detection sensor 2100: Heater plate 2200: Heater housing 2300: Heating coil tube 3000: Case 3110: Bottom support 3120: Rear support 3150: Cover part 3200: Connecting member 3300: Side support 4010: Regulator 4100: Power control unit 4200: Safety valve 4220: Safety valve drain pipe 4600: Cold water inlet pipe coupler 4700: Hot water discharge pipe coupler

Claims

Claim 1 An upper hot water tank comprising a first body portion having an open bottom and a first dome portion forming the top of the first body portion; The invention includes a lower hot water tank comprising a second body portion having an open top and a second dome portion forming the bottom of the second body portion; a first coupling portion in the form of an outwardly protruding flange with a first fusion annular projection formed on the bottom surface of the upper hot water tank is formed at the bottom of the upper hot water tank, and a second coupling portion in the form of an outwardly protruding flange with a second fusion annular projection formed on the top surface of the upper hot water tank is formed at the top of the lower hot water tank; an upper pipe is formed inside the upper hot water tank with its top connected to the first dome portion and its bottom extending to the first coupling portion, and a lower pipe is formed inside the lower hot water tank with its bottom connected to the second dome portion and its top extending to the second coupling portion; as the first fusion annular projection and the second fusion annular projection melt, the first coupling portion and the second coupling portion are heat-fused to form an outwardly protruding heat-fused portion to form the hot water tank, and the upper pipe and the lower pipe are fused to each other so that the inside of the hot water tank An electric water heater having a heat-fusion bonded hot water tank characterized by forming an internal hot water discharge pipe connected in the height direction. Claim 2 An electric water heater having a heat-fusion bonded hot water tank, wherein, in claim 1, the heat-fusion portion is formed in the shape of a reinforcing flange protruding outward. Claim 3 An electric water heater having a heat-fusion bonded hot water tank, characterized in that, in paragraph 2, the first body portion of the upper hot water tank comprises a plurality of stepped portions in which the outer surface of the upper body portion is steppedly reduced toward the first dome portion and a step portion between the stepped portions, or the second body portion of the lower hot water tank comprises a plurality of stepped portions in which the outer surface of the lower body portion is steppedly reduced toward the second dome portion and a step portion between the stepped portions. Claim 4 An electric water heater having a heat-fusion bonded hot water tank, characterized in that, in the second dome portion of the lower hot water tank, a heater mounting portion is formed to which a heater is inserted and mounted, a cold water inlet pipe for introducing cold water into the hot water tank, and a hot water outlet pipe for discharging hot water inside the hot water tank to the outside is formed to extend downward. Claim 5 An electric water heater having a heat-fusion bonded hot water tank, characterized in that, in paragraph 4, an outlet hole is formed at the upper part of the upper pipe for discharging hot water inside the hot water tank. Claim 6 An electric water heater having a heat-fusion bonded hot water tank, characterized in that, in claim 5, the first dome portion of the upper hot water tank is provided with an alignment rod positioned parallel to the upper pipe on the outside, and the alignment rod and the lower pipe serve as a reference for alignment when the upper hot water tank and the lower hot water tank are heat-fused. Claim 7 An electric water heater having a heat-fusion bonded hot water tank, characterized in that, in claim 4, the hot water discharge pipe comprises: an external hot water discharge pipe extending to the lower part of the lower hot water tank and coupled with a hot water discharge pipe coupler; and an internal hot water discharge pipe connected to the external hot water discharge pipe and serving as a path for the movement of hot water inside the hot water tank. Claim 8 An electric water heater having a heat-fused bonded hot water tank, characterized in that, in paragraph 3, a reinforcing band made of metal material is mounted on the stepped portion of the hot water tank to restrain the outer surface of the hot water tank against expansion pressure. Claim 9 An electric water heater having a heat-fusion bonded hot water tank, wherein, in claim 1, the case includes a case that accommodates the hot water tank inside, the case includes a lower support portion to which a cold water inlet pipe coupler and a hot water outlet pipe coupler are combined, a rear support portion fixed to a wall, and a cover portion covering the front, and the rear support portion is fixed to a side support portion that supports the load of the hot water tank by engaging with the heat-fusion portion of the hot water tank. Claim 10 An electric water heater having a heat-fusion bonded hot water tank, characterized in that, in claim 9, a fixing rod is formed protruding from the upper surface of the hot water tank, and a connecting member is provided on the rear support portion of the case to be coupled to the fixing rod and to support the hot water tank toward the rear support portion.

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