Hot water storage tank of a hot water supply device

Abstract

To provide a water heater reducing cost due to thinning and weight saving of a shell plate of a water storage tank by a reinforcement ring, resisting positive pressure, negative pressure and repeated pressure, excellent in heat insulation capacity, and having high versatility.SOLUTION: A water storage tank 4 for a water heater includes: an almost cylindrical shell plate 15; an almost hemispherical upper plate 14 disposed above the shell plate 15; an almost hemispherical lower plate 16 disposed below the shell plate 15; a reinforcing ring 23 disposed on the outer periphery of the shell plate 15 and having fastening parts on its both ends; and a vacuum heat insulation material 28 disposed on the outer periphery of the reinforcing ring 23 and at least partly covering the shell plate 15 and the reinforcing ring 23. The upper and lower end face parts in the longitudinal direction of the reinforcing ring are subjected to bending processing.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a hot water storage tank that is used as a water heater and stores hot water heated to an arbitrary temperature.

Background Art

[0002] Conventionally, as water heaters, water heaters that use gas or oil as fuel and heat tap water with the combustion heat have been used. These have the advantage of excellent quick-heating performance, but on the other hand, they require fuels such as gas and oil, and their supply is indispensable. The exhaust gas after combustion is released into the atmosphere, causing air pollution. Since they are combusted, there is always an inherent risk of insecurity, and there are problems such as loud noise during combustion. In particular, in all-electric houses and condominiums where all energy sources are electric, which have been increasing in recent years, there is no way to supply fuel, so the number of cases where a water heating device that heats tap water with combustion heat cannot be used is also increasing. Therefore, a water heater equipped with a large-capacity hot water storage tank for storing heated hot water has been developed. As this heating method, inexpensive off-peak electricity is used, and hot water generally at 80°C or higher, which is heated by an electric heater disposed inside the hot water storage tank at night, is stored in the hot water storage tank. This hot water and tap water are mixed to a desired arbitrary temperature and supplied from a water supply terminal. In addition, as a heating method, a storage - type heat pump water heater that uses a heat pump in addition to a heater has been developed. This is equipped with a large - capacity hot water storage tank and an outdoor unit incorporating a heat pump circuit. Utilizing inexpensive off - peak electricity at night, it heats tap water with the heat pump circuit to generate hot water, stores the hot water in the hot water storage tank, mixes this hot water with tap water to the desired temperature for the user, and supplies it from the hot water supply terminal. Since this heat pump water heater uses the state change of the refrigerant for heating, it has better energy efficiency than heating with an electric heater, can ensure a capacity more than three times that of the input, and also has a lower running cost. Therefore, it solves the problems of water heaters by combustion and can be easily installed without the need for new infrastructure even in all - electric houses and condominiums, and has been spreading. In the case of the hot water storage tank of the water heater used in this way, the water pressure from the water supply directly acts on the hot water storage tank, causing deformation, and repeated loads due to the opening and closing operations of the hot water supply terminal are applied. To prevent cracks and water leakage, a pressure reducing valve is provided between the water supply part of the water supply and the hot water storage tank to reduce the pressure applied to the hot water storage tank. And this setting is usually set from 100 kPa to several hundred kPa. However, due to the installation of such a pressure reducing valve, the water pressure at the hot water supply terminal is reduced, the shower pressure becomes low, and the power of the shower weakens. When supplying hot water at a high place such as supplying hot water to the third floor in a three - story house, problems such as low flow rate and long time consumption have emerged. In addition to the positive pressure described above, negative pressure also occurs in the hot water storage tank. Due to the opening and closing operation of the hot water supply terminal, an opening and closing operation timing difference occurs because the opening and closing operation of the hot water outlet terminal is delayed with a time difference compared to the water supply part, the internal pressure of the hot water storage tank decreases, and the pressure becomes lower than the external pressure (outside pressure) of the hot water storage tank, so - called negative pressure occurs in the hot water storage tank. Usually, to prevent excessive negative pressure from occurring in the hot water storage tank, a relief valve component that releases the pressure inside the hot water storage tank when negative pressure occurs is configured. However, in case of relief valve failure, the hot water storage tank is required to have a high negative pressure resistance strength. For the negative pressure resistance strength of the hot water storage tank, it is necessary to simply increase the strength of the hot water storage tank. In order to increase the pressure resistance of the hot water storage tank, generally, the plate thickness is increased in many cases. However, the hot water storage tank material is mostly made of expensive stainless steel to prevent corrosion, and increasing the plate thickness will lead to an increase in the material cost. In addition to increasing the plate thickness, the tank strength is improved by the following measures. This type of hot water supply device with hot water storage incorporates a hot water storage tank, and a thin-walled and lightweight tank is required in terms of environmental consideration, cost, transportation, and installation. As a countermeasure against negative pressure generated in the hot water storage tank, in addition to increasing the plate thickness, the tank strength is improved by the following measures. As shown in Fig. 6(a), a reinforcing ring 123 (see Fig. 6(b)) is attached to the body 104 of the hot water storage tank to take countermeasures against negative pressure. In the sealed body 104 of the hot water storage tank, when a large negative pressure is applied inside the body 104 of the hot water storage tank, deformation as shown in Fig. 6(c) occurs. That is, when a depression occurs in a part of the circumferential surface of the body 104 of the hot water storage tank and becomes concave, the other parts protrude convexly, and the circumferential surface of the body 104 of the hot water storage tank is unevenly deformed. Therefore, the reinforcing ring 123 fixed to the outer peripheral surface of the body 104 of the hot water storage tank prevents the uneven deformation of the body 104 of the hot water storage tank, improves the negative pressure resistance performance, and makes it difficult for uneven deformation to occur. (For example, see Patent Document 1)

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] A hot water storage and supply device is required to have both pressure resistance performance and heat retention performance. Heat retention performance can be improved by covering and insulating with low thermal conductivity components. The hot water storage tank improves heat retention performance by directly attaching a vacuum insulation material VIP (Vacuum Insulation Panel) component with a substantially vacuum inside to the outer peripheral surface of the body portion 104 of the hot water storage tank. However, the reinforcing ring 123 disposed on the outer peripheral surface of the body portion 104 of the hot water storage tank has an edge surface configured in the outer peripheral direction. Since the edge surface contacts and cuts the VIP component surface of the vacuum insulation material, the VIP component of the vacuum insulation material cannot be directly attached to the outer periphery of the reinforcing ring 123 of the body portion 104 of the hot water storage tank, resulting in a problem of reduced heat retention performance. In addition, since the body portion 104 of the hot water storage tank with a large capacity has an extended body length, the displacement amount of the body portion 104 of the hot water storage tank with respect to pressure increases. Therefore, a plurality of reinforcing rings 123 are provided, but the VIP component of the vacuum insulation material avoids being damaged by the edge of the reinforcing ring 123, resulting in an arrangement in which the high-temperature portion of the hot water storage tank is exposed, and there is a problem of reduced heat retention performance.

[0005] The present invention solves the above-mentioned conventional problems and aims to provide a hot water storage tank of a hot water supply device that achieves both pressure resistance strength and heat retention performance of the hot water storage tank.

Means for Solving the Problems

[0006] In order to solve the above-mentioned conventional problems, the hot water storage tank of the hot water supply device of the present invention includes a substantially cylindrical body plate, a substantially hemispherical upper plate disposed above the body plate, a substantially hemispherical lower plate disposed below the body plate, a reinforcing ring disposed on the outer periphery of the body plate and having fastening portions at both ends, and a vacuum insulation material disposed on the outer periphery of the reinforcing ring and covering at least a part of the body plate and the reinforcing ring. The hot water storage tank of the hot water supply device is characterized in that bending processing is performed on the upper and lower end faces in the longitudinal direction of the reinforcing ring. Thereby, the reinforcing ring can be covered with the vacuum insulation material 28 without damaging the vacuum insulation material. Therefore, it becomes a thin-walled and lightweight hot water storage tank having pressure resistance strength and a hot water storage tank capable of ensuring heat retention performance.

Effects of the Invention

[0007] The present invention solves the above-described conventional problems, and by means of a reinforcing ring, it is possible to reduce costs by making the body plate of the hot water storage tank thinner and lighter, withstand positive pressure, negative pressure, and repeated pressure, have excellent heat retention performance, and provide a highly versatile hot water storage tank.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Embodiments for Carrying Out the Invention

[0009] A first invention is a hot water storage tank of a water supply device, comprising a substantially cylindrical body plate, a substantially hemispherical upper plate disposed above the body plate, a substantially hemispherical lower plate disposed below the body plate, a reinforcing ring disposed on the outer periphery of the body plate and having fastening portions at both ends, and a vacuum heat insulating material disposed on the outer periphery of the reinforcing ring and covering at least a part of the body plate and the reinforcing ring, wherein the upper and lower end faces in the longitudinal direction of the reinforcing ring are subjected to bending treatment. Thereby, by performing curling or hemming treatment, the edge portion due to the end face does not face outward. Therefore, the reinforcing ring can be covered with the vacuum heat insulating material without damaging the vacuum heat insulating material. Thus, a thin-walled and lightweight hot water storage tank having pressure resistance strength and a hot water storage tank capable of ensuring heat retention performance can be obtained. Safety can be ensured and a reinforcing effect can be obtained by bending treatment. When hemming treatment or curling treatment is performed, the end cut surface is folded inward, and the bent portion becomes curved. Since the upper and lower end faces are no longer sharp, safety is obtained. In the case of a thin metal plate, if the end face is left as it is without bending, there is a risk of injury, but if bending treatment is performed, it is not necessary to directly touch the sharp end face, so the risk of injury is eliminated. Due to hemming bending or curling shape, the plate thickness of the bent portion is doubled, so a reinforcing effect can be obtained. Bending treatment is mainly applied to thin metal plates, but even a metal plate with low strength as it is can increase in thickness and strength by hemming or curling bending treatment. The end face of the metal plate often comes into contact with the vacuum heat insulating material during assembly or installation and transportation, and there is a possibility of damage or deformation. However, since it is reinforced by hemming bending or curling shape, damage and deformation can be prevented.

[0010] The second invention is that a flat bead is provided on the metal plate of the reinforcing ring. Conventionally, the reinforcing ring is formed by bending a strip-shaped metal plate into a ring shape and opposing both ends, and fastening these ends together with another component such as a screw. The metal plate of the reinforcing ring is often composed of a flat surface, but by applying a bead shape using drawing processing, the section modulus can be increased and the strength of the reinforcing ring itself can be reinforced. As a result, the shape of the reinforcing ring with increased strength can increase the strength if it has the same thickness as the conventional one, or can be thinned if it has the same strength as the conventional one. Thinning of the reinforcing ring leads to a smaller diameter of the hot water storage tank. A smaller diameter of the hot water storage tank enables miniaturization of the entire hot water supply device, or if it is a hot water supply device of the same size, by utilizing the empty space due to the smaller diameter of the reinforcing ring, the thickness of the vacuum heat insulating material can be increased, and a hot water storage tank with excellent heat insulation performance can be provided.

[0011] The third invention is that the reinforcing ring is in contact with the body plate. As a result, by reducing the contact area between the hot water storage tank that stores high-temperature water by boiling and the reinforcing ring through point contact at the curled portion or bead portion, heat transfer becomes more difficult than in the case of surface contact of the conventional shape. Therefore, it is possible to provide a hot water storage tank with improved heat insulation performance.

[0012] A fourth invention is one in which a plurality of the reinforcing rings are arranged on the barrel plate. The hot water storage tank becomes a so-called long-barrel tank in which the axial portion of the same plate becomes longer in proportion to the tank capacity. As the length of the barrel portion increases, the pitch with the upper and lower end plates widens and expands. As a result, the amount of deformation due to pressurization and depressurization increases in proportion to the pitch amount. To reduce the pitch interval, the depth of the end plate can be increased, but deep drawing of the press is correlated with thinning of the plate thickness, and deep drawing is limited by thinning. Therefore, by using a plurality of reinforcing rings, tank deformation can be suppressed, and a tank with a wide pitch interval can be configured even with a thin wall.

[0013] Hereinafter, embodiments will be described in detail with reference to the drawings. However, a more detailed description may be omitted as necessary. For example, detailed descriptions of well-known matters or duplicate descriptions of substantially the same configuration may be omitted. It should be noted that the accompanying drawings and the following description are provided for those skilled in the art to fully understand the present disclosure, and are not intended to limit the subject matter described in the claims.

[0014] (Embodiment 1) Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a front internal view of a hot water supply device according to Embodiment 1 of the present invention. The hot water supply device includes a hot water storage tank unit 1 and a heat pump unit 2 having a heat pump circuit. The hot water storage tank unit 1 and the heat pump unit 2 are connected by two water pipes 3 (3a, 3b). Inside the hot water storage tank unit 1 of the hot water supply device, there is a hot water storage tank 4 for storing the hot water heated by the heat pump unit 2. Tap water is heated by the heat pump unit 2 and stored as hot water. When necessary, it can be mixed with tap water to be heated to a predetermined temperature for hot water supply. This hot water storage tank 4 is composed of a press part made of stainless steel with excellent corrosion resistance for thin plates and is cylindrical. In front of this hot water storage tank 4, there is a water supply pipe 5 for supplying tap water, and a pressure reducing valve 6 for reducing the pressure of the tap water supplied from this water supply pipe 5 to a certain pressure is arranged. In addition, functional components such as a water pump 7 and control components such as a control board 8 are arranged.

[0015] Conventionally, the pressure of tap water has been reduced to 120 kPa or less by the pressure reducing valve 6 and supplied to the hot water storage tank 4. By reducing the pressure applied to the hot water storage tank 4 in this way, deformation prevention and durability improvement of the hot water storage tank 4 are ensured. In recent years, as high-pressure type hot water storage tanks 4, there are those with the setting of the pressure reducing valve 6 increased to 170 kPa and high-pressure type hot water storage tanks 4 with the setting of the pressure reducing valve 6 at 280 kPa or more. A strainer is incorporated in the pressure reducing valve 6, and the strainer removes dust and contamination in the tap water. The pressure relief safety valve 9 is a device for discharging abnormal pressure in the hot water storage tank 4 which is a sealed pressure vessel, and is set higher than the set pressure of the pressure reducing valve 6, for example, higher than 280 kPa. There is also a high-pressure type in the hot water supply device with the water-side operating pressure changed. This type sets the set pressure of the pressure reducing valve 6 at 170 kPa or more to have a product lineup of various pressures, thus meeting the diverse needs of customers. The present invention is not limited to the high-pressure type and can be applicable to various operating pressures, and the present invention is not limited to the operating pressure.

[0016] The heat pump unit 2 incorporates a refrigerant cycle in which a compressor 10, a radiator 11, a pressure reducing means (not shown), and an air-refrigerant heat exchanger 12 are sequentially connected. The radiator 11 is a water-refrigerant heat exchanger that heats tap water. The blower fan 13 is a blowing means arranged in front of the air-refrigerant heat exchanger 12, which sucks air from the air-refrigerant heat exchanger 12, enhances the evaporation capacity, and enhances the heat pump heating capacity. Then, the tap water heated to 80 °C or higher by the heat pump unit 2 becomes hot water and is carried through the water pipe 3 (3b) to the hot water storage tank unit 1 of the water heater and stored in the hot water storage tank 4.

[0017] Figure 2 is a circuit diagram of the water heater in Embodiment 1 of the present invention. Hereinafter, the operation of the water heater will be described with reference to the drawings. The tap water supplied from the water supply pipe 5 once enters the inside of the hot water storage tank 4. From the hot water storage tank 4, it is sent through the water pipe 3 (3a) via the water pump 7 to the heat pump unit 2. In the heat pump unit 2, when the compressor 10 is driven, the refrigerant compressed to a high pressure and discharged is sent to the radiator 11, which is a water-refrigerant heat exchanger, where it exchanges heat with the tap water sent from the water pipe 3 (3a) and dissipates heat. As a result, the tap water is heated to a high temperature and is sent again to the hot water storage tank unit 1 through the other water pipe 3 (3b). The hot water that has become hot and returned to the hot water storage tank unit 1 is stored in the hot water storage tank 4. Then, when a hot water supply operation is performed, the hot water in the hot water storage tank 4 and the tap water supplied from the water supply pipe 5 via the pressure reducing valve 6 are mixed by the mixing valve 20, reach a predetermined temperature, and are supplied as hot water to the hot water supply terminal 22 such as a faucet or a bathtub through the hot water supply pipe 21. At this time, a pressure reducing valve 6 for reducing the pressure is provided in the water supply pipe 5 so that the pressure of the tap water does not act on the hot water storage tank 4, and the pressure is reduced to about 280 kPa. As a result, when the hot water supply terminal 22 is turned on and off, a pressure variation of about several tens of kPa and 280 kPa, which is the set pressure of the pressure reducing valve 6, are repeatedly applied to the hot water storage tank 4. Also, the pressure until the pressure relief safety valve 9 is opened when the temperature inside the hot water storage tank 4 rises and the internal pressure increases acts on the hot water storage tank 4. Therefore, the barrel plate 15 of the hot water storage tank 4 expands and contracts repeatedly at the center with the joints 15a (see FIG. 3) between the upper plate 14 (see FIG. 3) and the barrel plate 15 (see FIG. 3) and the joints 15b (see FIG. 3) between the lower plate 16 (see FIG. 3) and the barrel plate 15, which are welded by Tig welding, as the fulcrums. At the same time, the top 14a of the upper plate 14 and the lower plate 16 also expand and contract repeatedly. Since the strength of the upper plate 14, the barrel plate 15, and the lower plate 16 is increased, cracks do not occur, and a hot water storage tank 4 with excellent durability can be obtained. Therefore, the pressure of the pressure reducing valve 6 can be set high, the hot water supply shower pressure can be increased, and the usability is greatly improved and the operability is very good due to the increased momentum of the shower.

[0018] Also, when the pressure reducing valve 6 fails, pressure relief is performed at the pressure set by the pressure relief safety valve 9, and the internal pressure is applied to the hot water storage tank 4 up to that pressure. This set pressure is higher than the set pressure of the pressure reducing valve 6, but no abnormality occurs because the strength of the hot water storage tank 4 is improved. When the pressure reducing valve 6 and the pressure relief safety valve 9 are provided, pressures higher than those of the pressure reducing valve 6 and the pressure relief safety valve 9 are not applied to the hot water storage tank 4. However, if it is below the set pressure of the pressure relief safety valve 9, it is required that there be no water leakage, deformation, damage or other abnormalities when the static water pressure is applied. If it is above the set pressures of the pressure reducing valve 6 and the pressure relief safety valve 9, it is necessary that there be no water leakage, deformation, damage or other abnormalities. Since it is assumed that there may be cases where it is used exceeding the set pressure of the pressure relief safety valve 9, the strength is such that no water leakage, deformation, damage or other abnormalities occur when the static water pressure is applied.

[0019] In addition to the positive pressure described above, negative pressure is also generated in the hot water storage tank 4. When the opening and closing operation of the hot water supply terminal 22 causes the opening and closing operation of the hot water outlet terminal to be delayed with a time difference compared to the water supply section, an opening and closing operation timing deviation occurs, the internal pressure of the hot water storage tank 4 decreases, and the pressure inside the hot water storage tank 4 becomes lower than the external pressure (outside pressure) of the hot water storage tank 4, so-called negative pressure is generated inside the hot water storage tank 4. Usually, the pressure relief safety valve 9 has a function of releasing the pressure inside the hot water storage tank 4 when negative pressure is generated so that excessive negative pressure does not occur in the hot water storage tank 4. However, in preparation for a failure of the pressure relief safety valve 9, the hot water storage tank 4 is required to have a negative pressure resistance strength. It is necessary to simply increase the strength of the hot water storage tank 4 for the negative pressure resistance strength of the hot water storage tank 4. To increase the pressure resistance of the hot water storage tank 4, there are a change in the material of the hot water storage tank 4 and an increase in the plate thickness. Generally, in many cases, the plate thickness is increased to cope with it. However, in most cases, the material of the hot water storage tank 4 is made of expensive stainless steel to prevent corrosion, and increasing the plate thickness will lead to an increase in the cost of the material cost.

[0020] The configuration of the hot water storage tank 4 of the hot water supply device is shown in FIG. 3. FIG. 3(a) is a top view, and FIG. 3(b) is a side view. The upper plate 14 is formed by drawing a stainless steel plate having corrosion resistance, and the body plate 15 is a stainless steel plate integrated with the upper plate 14 by Tig welding. The body plate 15 is formed into a cylindrical shape by rolling a flat plate and is Tig welded in the vertical direction. The lower plate 16 is arranged below the body plate 15 and is integrated with the body plate 15 by Tig welding, and is formed by drawing a stainless steel plate in the same manner as the upper plate 14. The upper plate 14, the body plate 15, and the lower plate 16 form a closed space, and by storing warm water in the closed space, the role of the hot water storage tank 4 of the hot water supply device is fulfilled. In addition, a plurality of pipe connection parts 14d, 14e, 14f, 16d, 16e, 16f, which are water inlets and hot water outlets, are provided on the upper plate 14 and the lower plate 16. The legs 17 support the hot water storage tank 4, and the leg fittings 18 for holding the legs 17 are attached to the body plate 15 by spot welding. A reinforcing ring 23 for preventing deformation of the hot water storage tank 4 due to negative pressure applied to the hot water storage tank 4 is installed on the body plate 15.

[0021] FIG. 4 is a detailed enlarged view of the reinforcing ring 23 of the water heater. The reinforcing ring 23 shown in FIG. 4 is attached to the outer peripheral surface of the cylindrical body plate 15. The reinforcing ring 23 is formed by bending a strip-shaped metal plate 24 into a ring shape so that both ends of the metal plate 24 face each other. At each end, a metal L-shaped fastening part 25 that has been bent into an L shape is attached by welding or crimping. The L-shaped fastening parts 25 are opposed to each other and fastened to the body plate 15 with a fastening screw (not shown) with appropriate torque without looseness or excessive tightening. The upper and lower end faces 26 in the longitudinal direction of the reinforcing ring 23 are subjected to a bending process such as a so-called curling process or hemming process. By the bending process, the end face 26a of the upper and lower end faces 26 abuts against the outer peripheral surface of the metal plate 24. The hemming process is a process of folding back the upper and lower end faces 26 of the metal plate 24 by 180° and then flattening them, and the curling process is a process of rounding the upper and lower end faces 26 of the metal plate 24. By performing such a bending process, the edge portion due to the end face 26a does not face outward. Therefore, the reinforcing ring can be covered with the vacuum insulation material 28 without damaging the vacuum insulation material. Thus, a thin-walled and lightweight hot water storage tank having pressure resistance and a hot water storage tank capable of ensuring heat retention performance are obtained.

[0022] Safety can be ensured and a reinforcing effect can be obtained through bending processing. When hemming processing or curling processing is performed, the end face 26a is folded to the inside of the metal plate 24, and the bent portion becomes a curved surface. Since the upper and lower end face portions 26 are no longer sharp, safety is obtained. In the case of the thin metal plate 24, if the end face 26a is left as it is without bending, there is a risk of injury. However, if bending processing is performed, there is no need to directly touch the sharp end face 26a, so the risk of injury is eliminated. Due to hemming bending or curling shape, the plate thickness of the bent portion is doubled, so a reinforcing effect is obtained. Bending processing is mainly applied to the thin metal plate 24. Even the metal plate 24 with low strength as it is can increase in thickness and strength through hemming or curling-shaped bending processing. Since the end face 26a of the metal plate 24 has many opportunities to touch other parts during assembly, there is a possibility of scratches or deformation. However, since it is reinforced by hemming bending or curling shape, scratches and deformation can be prevented. Also, a flat bead 27 is provided on the flat portion of the reinforcing ring 23 to produce a rib effect, thereby increasing the strength. Due to the flat bead 27, the reinforcing ring 23 can be made thin while maintaining the strength. Although the metal plate 24 of the reinforcing ring 23 is often configured flat, by providing the flat bead 27 in the bead shape using drawing processing, the section modulus can be increased and the strength of the reinforcing ring 23 itself can be reinforced. As a result, the reinforcing ring 23 with increased strength can have higher strength if it has the same thickness as before, or can be made thinner if it has the same strength as before. The thinning of the reinforcing ring 23 leads to a reduction in the diameter of the hot water storage tank 4. The reduction in the diameter of the hot water storage tank 4 can reduce the size of the entire water supply device, or if the water supply device has the same size, the capacity of the hot water storage tank 4 can be increased by thinning the reinforcing ring 23.

[0023] The reinforcing ring 23 according to this embodiment is also designed to ensure strength against the negative pressure generated in the hot water storage tank 4. By attaching the reinforcing ring 23 to the body plate 15, the negative pressure resistance of the hot water storage tank 4 is improved. By fixing the reinforcing ring 23 to the outer peripheral surface of the cylindrical body plate 15, it is possible to prevent the convex and concave deformation of the body plate 15 due to the pressure difference when negative pressure is generated in the hot water storage tank 4, and the negative pressure resistance performance is improved.

[0024] Next, the heat insulation structure of the hot water storage tank unit 1 will be described. FIG. 5 is a side sectional view of the hot water storage tank unit in Embodiment 1 of the present invention. For the hot water storage tank 4, the upper plate 14 is covered with the tank upper heat insulating material 29, and the lower plate 16 is covered with the tank lower heat insulating material 31. Also, the body plate 15 of the hot water storage tank 4 has a configuration in which the tank side heat insulating material 30 is arranged. The tank upper heat insulating material 29, the tank side heat insulating material 30, and the tank lower heat insulating material 31 are formed of polystyrene foam or urethane foam that is easy to process. In the radial direction (normal direction) of the hot water storage tank 4, a vacuum heat insulating material 28 is arranged. Here, the vacuum heat insulating material 28 is formed of a core material and an outer skin material that covers the entire circumference of the core material. And the outer skin material of the vacuum heat insulating material 28 is formed of aluminum foil. The aluminum foil of the vacuum heat insulating material 28 has a thermal conductivity of about 238 [W / m·K]. The vacuum heat insulating material 28 is arranged on the body plate 15 so that the aluminum foil becomes the outer peripheral surface. Also, the upper end portion of the vacuum heat insulating material 28 is in contact with the tank upper heat insulating material 29. Also, the lower end portion of the vacuum heat insulating material 28 is in contact with the tank lower heat insulating material 31. Also, the circumferential end portion of the vacuum heat insulating material 28 is also in contact with the tank side heat insulating material 30. A reinforcing ring 23 is formed between the outer circumference of the body plate 15 of the hot water storage tank 4 and the inner circumference of the vacuum heat insulating material 28. The hot water storage tank 4 is required to have pressure resistance performance and heat retention performance at the same time. The heat retention performance is improved by covering and insulating with low thermal conductivity components.

[0025] As described above, the hot water storage tank 4 of the hot water supply device of the present invention includes a substantially cylindrical body plate 15, a substantially hemispherical upper plate 14, a substantially hemispherical lower plate 16, a reinforcing ring 23 disposed on the outer periphery of the body plate 15, and a vacuum heat insulating material 28 disposed on the outer periphery of the reinforcing ring 23 and covering at least a part of the body plate 15 and the reinforcing ring 23. The upper and lower end face portions 26 in the longitudinal direction of the reinforcing ring 23 are subjected to a bending process such as a so-called curling process or hemming process. By performing such a bending process, the edge portion by the end face 26a does not face outward, so that the reinforcing ring 23 can be covered with the vacuum heat insulating material 28 without damaging or breaking the vacuum heat insulating material 28. As a result, the hot water storage tank 4 has a pressure-resistant strength and is a thin-walled and lightweight hot water storage tank 4 that can ensure heat retention performance.

[0026] In addition, the reinforcing ring 23 can reduce the cost by reducing the thickness and weight of the body plate 15 of the hot water storage tank 4, and can provide a hot water storage tank 4 that can withstand positive pressure, negative pressure, and repeated pressures, has excellent heat retention performance, and is highly versatile. Also, by raising the set pressures of the pressure reducing valve 6 and the pressure relief safety valve 9 to increase the shower pressure and strengthen the force of the shower, it becomes possible to use hot water at high places such as supplying hot water to the third floor in a three-story house, and the usability is greatly improved. Also, as a method of raising the shower pressure, there is a method of using a pressurizing pump. This is a method of installing a pressurizing pump on the outlet side of the hot water supply and raising the shower pressure by raising the hot water supply pressure. However, there are also problems such as the need for construction during installation and the additional cost of the pressurizing pump. On the other hand, by increasing the strength of the hot water storage tank 4 with the reinforcing ring 23 of the present invention and raising the set pressures of the pressure reducing valve 6 and the pressure relief safety valve 9, the shower pressure also increases, and as a result, the hot water filling time of the bathtub can be significantly shortened.

Industrial Applicability

[0027] As described above, the present invention is applied to a hot water supply device that stores and supplies hot water, and is suitable for, for example, a household heat pump hot water supply device.

Explanation of Reference Numerals

[0028] 1 Hot water storage tank unit 2 Heat pump unit 3, 3a, 3b Water pipes 4 Hot water storage tank 5 Water supply pipe 6 Pressure reducing valve 7 Water pump 8 Control board 9 Pressure relief safety valve 10 Compressor 11 Radiator 12 Air-refrigerant heat exchanger 13 Blower fan 14 Upper plate 14a Top 14d, 14e, 14f Pipe connection parts 15 Barrel plate 15a, 15b Joint parts 16 Lower plate 16d, 16e, 16f Pipe connection parts 17 Legs 18 Leg brackets 20 Mixing valve 21 Hot water supply pipe 22 Hot water supply terminal 23 Reinforcing ring 24 Metal plate 25 L-shaped fastening part (fastening part) 26 Upper and lower end faces 26a End face 27 Flat bead 28 Vacuum insulation material 29 Tank upper insulation material 30 Tank side insulation material 31 Tank lower insulation material

Claims

1. A substantially cylindrical body plate, A substantially hemispherical upper plate disposed above the body plate, A substantially hemispherical lower plate disposed below the body plate, A reinforcing ring disposed on the outer periphery of the body plate and having fastening portions at both ends, A vacuum heat insulating material disposed on the outer periphery of the reinforcing ring and covering at least a part of the body plate and the reinforcing ring, A hot water storage tank of a hot water supply device comprising: In the reinforcing ring, bending treatment is performed on the upper and lower end surfaces extending in the longitudinal direction, which is the same direction as the circumferential direction of the hot water storage tank, so that the end surface of the reinforcing ring is folded back to the outside with respect to the hot water storage tank. The hot water storage tank of the hot water supply device, in which the reinforcing ring is in line contact with the body plate.

2. The hot water storage tank of the hot water supply device according to Claim 1, wherein a flat bead having a bead shape is provided on the flat surface of the metal plate of the reinforcing ring.

3. The hot water storage tank of the hot water supply device according to any one of Claims 1 or 2, wherein a plurality of the reinforcing rings are disposed on the body plate. ​ ​ ​ ​

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