JP4737214B2 - Hot water storage tank of water heater and heat pump water heater using the same - Google Patents

Description

  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.

  Conventionally, hot water heaters that use gas or petroleum as fuel and heat tap water with the combustion heat have been used as hot water heaters. While these have the advantage of being excellent in quick hot water properties, fuels such as gas and oil are necessary and the supply thereof is indispensable, exhaust gas after combustion is released into the atmosphere, causing air pollution, and burning Therefore, there were problems such as being always unsafe and having a loud noise during combustion. Especially in all-electric houses and condominiums where all energy sources are electricity, which has been increasing in recent years, there is no way to supply fuel, so there are more cases where it cannot be used.

  In view of this, a hot water supply apparatus having a large-capacity hot water storage tank for storing heated hot water has been developed. As a heating method, hot water of 80 ° C or higher, which is generally heated by an electric heater installed in the hot water storage tank at night, is stored in the hot water storage tank. The hot water and tap water are mixed to obtain an arbitrary temperature desired by the user and supplied from the hot water supply terminal.

  As a heating method, a hot water storage type heat pump type hot water supply apparatus using a heat pump in addition to the heater has been developed. This is equipped with a large-capacity hot water storage tank and an outdoor unit that incorporates a heat pump circuit. Using cheap electricity at night discounts, tap water is heated to hot water using the heat pump circuit, and the hot water is stored in the hot water storage tank. The hot water and tap water are mixed to obtain an arbitrary temperature desired by the user and supplied from the hot water supply terminal. Since this heat pump type hot water supply apparatus is heated by utilizing the change in the state of the refrigerant, it is more energy efficient than heating by an electric heater, and the capacity for input can be secured three times or more, and the running cost is also low. It has become popular because it solves the problem of hot water heaters due to combustion, and can be installed easily in all-electric houses and condominiums without the need for new infrastructure.

  In the case of a hot water storage tank of a hot water supply device used in this way, the water pressure from the water supply is directly applied to the hot water storage tank, it is deformed, a repeated load is applied due to the opening and closing operation of the hot water supply terminal, cracks occur, and water leaks. In order to prevent trapping, a pressure reducing valve is provided between the water supply unit and the hot water storage tank to reduce the pressure applied to the hot water storage tank. This setting is usually set from 100 kPa to 200 kPa. However, because such a pressure reducing valve is provided, the water pressure at the hot water supply terminal decreases, the shower pressure decreases, and the momentum of the shower disappears. When hot water is supplied, there are problems such as low flow rate and time.

  To prevent this, it is necessary to increase the strength of the hot water storage tank. In order to increase the pressure resistance of such a hot water storage tank, in many cases, the plate thickness is generally increased. However, in most cases, the material of the hot water storage tank is made of stainless steel in order to corrode, and increasing the plate thickness leads to an increase in material costs.

  In addition to increasing the plate thickness, the following measures are taken.

A plurality of reinforcing ribs 55 are provided on the body plate 54 of the hot water storage tank 53 in the shape shown in FIG. 8. The reinforcing ribs 55 are narrow at the center of the body plate 53 and wide at both ends of the body plate 53. Similarly, the strength against negative pressure is improved. Moreover, although these have raised the intensity | strength with respect to a negative pressure, naturally the intensity | strength with respect to a positive pressure is also considered to have improved a little (for example, refer patent document 1).
JP-A-3-148484

  However, in the above-described conventional configuration, in order to project the reinforcing rib 55 outwardly from the body plate 54, it is necessary to project the body plate 54 by roll processing or perform hydroforming after tank processing. It is. If it overhangs at the time of the roll processing, it becomes difficult to keep a perfect circle, and it becomes a distorted state. Therefore, it is very difficult to complete the tank of the hot water storage tank 53 by fitting with the upper plate 146 and the lower plate 57 above and below the trunk plate 54.

  In addition, the hydroforming process is to deform the body plate 54 by applying water pressure after completion of the tank. However, when processing is to be performed in a tank exceeding 300 L, the apparatus is very large, An excessive pressure is required, and the cost is greatly increased.

  Further, under the condition where a positive pressure is applied, the structure of projecting the ribs outward is not sufficient, and even if the reinforcing ribs 55 are provided, there is almost no effect, but rather the stress is deteriorated. In order to clear this, it is necessary to increase the plate thickness of the body plate 54. If the plate thickness is increased, the cost increases when the material is stainless steel, and the ribs for the reinforcing rib 55 are processed. However, there is a problem that roll processing and hydroforming processing are difficult to perform, which eventually leads to further cost increase.

  The present invention solves the above-described conventional problems, can withstand positive pressure, negative pressure, and repeated pressure, is advantageous in terms of cost, and can be used without greatly changing the main body configuration, and has high usability. It aims at providing the hot water storage tank of a hot-water supply apparatus.

In order to solve the above-mentioned conventional problems, the hot water storage tank of the hot water supply apparatus of the present invention stores hot water heated to an arbitrary temperature using a heating means, and is substantially hemispherical above and below the substantially cylindrical body plate. The upper plate and the lower plate are respectively disposed, and the vertical cross-sectional shape of the top portion of the upper plate and the lower plate is 1.1 to 1.3 times the long side with respect to the diameter of the substantially hemispherical plane circle, An elliptical shape with a short side of 0.4 to 0.6 times, and a pipe connection portion provided on the upper plate and / or the lower plate is integrally formed in the normal direction of the elliptical surface of the upper plate and / or the lower plate Alternatively, the chamfered shape of a portion where the substantially hemispherical outer periphery substantially vertical portion and the elliptical shape are connected is a part of a circular shape having a radius of 80 mm or more, and the water supply unit for supplying tap water and the water supply unit And a pressure reducing valve for reducing the feed water pressure, and the set pressure of the pressure reducing valve is 0.25. Characterized in that the above Pa, repeated pressure - when the pressure was reduced, the upper plate, joined by repeated load on the lower plate, in this case, the root portion of the pipe connection portion is large stress Although it works, it is possible to reduce the stress by making the pipe connection part in the normal direction, prevent cracks in the pipe connection part, and make a hot water storage tank with excellent durability It is possible to improve quality.

  According to the present invention, there is provided a hot water storage tank for a hot water supply device that can withstand positive pressure, negative pressure, and repeated pressure, is advantageous in terms of cost, and can be used without greatly changing the main body configuration. it can.

In the first invention, hot water heated to an arbitrary temperature using a heating means is stored, and a substantially hemispherical upper plate and a lower plate are disposed above and below a substantially cylindrical body plate, respectively. The longitudinal cross-sectional shape of the top part of the said upper board and the lower board is 1.1-1 long side with respect to the diameter of a substantially hemispherical plane circle.
. The elliptical shape of 3 times the short side 0.4 to 0.6 times, and the pipe connection portion provided on the upper plate and / or the lower plate, the normal direction of the elliptical surface of the upper plate and / or the lower plate The chamfered shape of the part where the substantially hemispherical outer periphery substantially vertical part and the elliptical shape are in contact with each other is a circular part having a radius of 80 mm or more, and a water supply part for supplying tap water. A hot water storage tank of a hot water supply apparatus comprising: a pressure reducing valve for reducing a water supply pressure in the water supply unit; and a set pressure of the pressure reducing valve is set to 0.25 MPa or more .

As a result, when repeated pressurization and depressurization are performed, a repeated load is applied to the upper plate and the lower plate, and at that time, a large stress acts on the root portion of the pipe connection portion. By adopting the normal direction, the stress can be reduced, cracks at the pipe connection can be prevented, and a hot water storage tank with excellent durability can be achieved, thereby improving quality. be able to.

Further, when a hydrostatic pressure of 1.75 MPa is applied to the hot water storage tank, it is possible to realize that there is no water leakage, deformation, breakage or other abnormality, and that the static pressure applied to the hot water storage tank with the hot water supply terminal opened is 20. It is possible to prevent cracks in the upper and lower plates when it is repeatedly pressurized and depressurized to 330 kPa, which is the static pressure applied to the hot water storage tank with the hot water supply terminal closed. In order to realize a hot water storage tank, the set pressure of the pressure reducing valve directly connected to the water supply can be set to a high setting of 200 kPa (0.2 MPa) or more, and the shower pressure is increased to increase the momentum of the shower. In order to supply hot water at high places, such as hot water supply at the third floor in a three-story house, it becomes possible to increase the hot water supply pressure, and the usability is greatly improved.

The second invention is a hot water storage tank of a hot water supply apparatus characterized in that the plate thickness of the body plate is equal to or greater than the plate thicknesses of the upper plate and the lower plate. Since the upper and lower plates are fixed to the upper plate and the lower plate, an equally distributed load fixed to both ends is applied. For this reason, the joint between the body plate, the upper plate, and the lower plate has the highest stress. Since the upper plate and the lower plate have a deep drawing configuration, they are strong in strength and are not easily deformed. On the other hand, the body plate is cylindrical and is deformed in the bulging direction toward the center because it is formed by roll processing. For this reason, there is a possibility that cracks due to repeated loads may occur at the joint portion between the upper and lower plates of the body plate having the highest stress. On the other hand, by increasing the thickness of the body plate relative to the thickness of the upper and lower plates, the strength of the body plate can be increased, and cracks at the joints can be prevented. This makes it possible to make a hot water storage tank that excels in quality, and to improve quality .

According to a third aspect of the present invention, the hot water storage device of the hot water supply apparatus is characterized in that the central position of the pipe connecting portion is located inward by 50 mm or more from the intersection of the elliptical portion and the chamfered portion at the top of the upper plate and the lower plate. When a hydrostatic pressure of 1.75 MPa is applied to the hot water storage tank, it can be realized that there is no water leakage, deformation, breakage or other abnormalities, and the static pressure applied to the hot water storage tank with the hot water supply terminal opened. When repeated pressurization and decompression of 20 to 60 kPa and 330 kPa, which is the static pressure applied to the hot water storage tank with the hot water supply terminal closed, can prevent cracks in the upper and lower plates, making it durable In order to realize an excellent hot water storage tank, it is possible to set the pressure setting of the pressure reducing valve directly connected to the water supply to a high setting of 200 kPa (0.2 MPa) or higher. Strong momentum That, or to hot water at heights such as third floor hot water in 3-story house, it is possible to use by raising the hot water supply pressure, so that the usability is greatly improved.

The fourth invention is formed by sequentially connecting a hot water storage tank of the hot water supply apparatus of any one of the first to third inventions, a compressor, a water-refrigerant heat exchanger, a pressure reducing means, and an air-refrigerant heat exchanger. A heat pump water heater characterized by comprising a heating means, and in a high-priced heat pump water heater, it is possible to secure heat insulation performance while reducing costs, and a water heater that can further increase the popularity can do.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a front view of the hot water supply apparatus of the present invention, and FIG. 2 is a circuit diagram of the hot water supply apparatus.

  Reference numeral 1 denotes a hot water storage tank unit of the hot water supply apparatus, and 2 denotes a heat pump unit 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 water heater, there is a hot water storage tank 4 for storing hot water heated by the heat pump unit 2, and the tap water is heated by the heat pump unit 2 and stored as hot water. It can be mixed with tap water to supply hot water at a predetermined temperature. The hot water storage tank 4 is made of a pressed part made of stainless steel having excellent corrosion resistance of a thin plate, and has a cylindrical shape. In front of the 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 water pressure supplied from the water supply pipe 5 to a constant water pressure is arranged. Functional parts such as the pump 7 and control parts such as the control P plate 8 are arranged.

  The pressure reducing valve 6 generally reduces the pressure of tap water to 120 kPa or less and supplies it to the hot water tank 4. By reducing the pressure applied to the hot water tank 4, the hot water tank 4 is prevented from being deformed and improved in durability. Secured. In recent years, as a high pressure type, a pressure reducing valve has been set up to 180 kPa. However, in this specification, the pressure reducing valve is set to 250 kPa or higher and increased to 280 kPa. The hot water storage tank unit 1 is used. In addition, a strainer is incorporated in the pressure reducing valve 6 to remove dust and contamination in the tap water.

  Reference numeral 9 denotes a pressure relief safety valve provided at the top dead center of the hot water storage tank 4 which is a sealed pressure vessel. As a device for releasing abnormal pressure in the can body to prevent the hot water storage tank 4 from bursting, It is set higher than the set pressure. In this specification, a setting higher than 280 kPa is set to about 340 kPa in consideration of variations of the pressure reducing valve 6.

  The heat pump unit 2 incorporates a refrigerant cycle in which a compressor, a radiator, a decompression unit, and an air-refrigerant heat exchanger are sequentially connected. 10 is a compressor, 11 is a radiator, and water-refrigerant heat exchange. As a vessel, a heat exchanger for heating tap water is provided, and 12 is an air-refrigerant heat exchanger. Reference numeral 13 denotes a blower fan which is a blower disposed in front of the air-refrigerant heat exchanger 12 so as to suck air from the air-refrigerant heat exchanger 12 to increase the evaporation capacity and to increase the heat pump heating capacity. It has become. Then, the tap water heated to 80 ° C. or higher by the heat pump unit 2 becomes hot water, is carried to the hot water storage tank unit 1 of the hot water supply device through the water pipe 3 b, and is stored in the hot water storage tank 4.

The structure of the hot water storage tank 4 of the hot water supply apparatus is shown in FIG. 3, and a top view is shown in FIG. 3 (a) and a side view is shown in FIG. 3 (b). 14 is an upper plate formed by drawing a stainless steel plate having corrosion resistance, and 15 is a stainless steel plate body integrated with the upper plate 14 by Tig welding. It is cylindrical and is Tig welded in the vertical direction. Reference numeral 16 denotes a lower plate disposed below the body plate 15 and 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. A closed space is formed by these three parts, and hot water is stored inside the closed space, thereby serving as a hot water storage tank of the hot water supply apparatus. Further, the upper plate 14 and the lower plate 16 are provided with a plurality of pipe connection portions 17 and 18 which are water supply ports and hot water outlets.

  The top plate 14 has an elliptical shape in which the top portion 14a has a long side B of 1.1 to 1.3 times and a short side C of 0.4 to 0.6 times the diameter A of a hemispherical planar circle. Yes. Further, the chamfered shape 14c of the portion where the outer peripheral vertical portion 14b and the apex portion 14a are in contact with each other is configured to be connected with a part of a circular shape having a radius of 80 mm or more.

  Although this configuration has been described for the upper plate 14, the same is true for the lower plate 16. Reference numeral 17 denotes a leg for supporting the hot water storage tank, and a leg fitting 18 for holding the leg 17 is attached to the body plate 15 by spot welding. Furthermore, the upper plate 14 and the lower plate 16 are provided with pipe connections for connecting water supply and hot water supply pipes, the upper plate 14 is provided with 14d, 14e, 14f, and the lower plate 16 is provided with 16d, 16e, 16f. ing.

  4 and 5 show detailed cross-sectional views of the upper plate 14. Of the pipe connecting portions 14d, 14e, and 14f, not only 14d in the center portion, but 14e and 14f have a shape processed in the normal direction with respect to the elliptical portion of the top portion 14a. That is, a hole is drilled in the normal direction of the top portion 14a, and the pipe socket 19 is welded to the hole processed portion, and the plate thickness is reduced by the processing of the pipe connecting portions 14d, 14e, and 14f. This is to prevent and to ensure strength.

  Further, the center position of the pipe opening 14j, that is, the center position of the pipe socket 19 is arranged inward by 50 mm or more from the intersection 14g of the elliptical shape of the top portion 14a and the chamfered shape 14c. Moreover, the intersection of the elliptical shape of the convex part 14i and the top part 14a is distribute | arranged inside the elliptical intersection of the chamfering shape 14c and the top part 14a.

  And the hot water storage tank 4 comprised in this way is the hot water storage tank unit 1 of a hot-water supply apparatus in the form shown in FIG. 1, FIG. Further, the plate thickness of the body plate 15 is equal to or greater than the plate thickness of the upper plate 14 and the lower plate 16.

  Hereinafter, the operation of the hot water supply apparatus will be described with reference to the drawings.

  The tap water supplied from the water supply pipe 5 once enters the hot water storage tank 4. The hot water storage tank 4 is sent to the heat pump unit 2 through the water pipe 3 (3a) via the pump 7. In the heat pump unit 2, when the compressor 10 is driven, the refrigerant compressed and discharged to a high pressure is sent to the radiator 1.1 which is a water-refrigerant heat exchanger, and here, from the water pipe 3 (3 a). Heat is exchanged with the tap water sent to dissipate heat.

  Thus, the tap water is heated to a high temperature and sent again to the hot water supply tank unit 1 through the other water pipe 3b. Hot water returned to the hot water tank unit 1 due to high temperature is stored in the hot water storage tank 4. When the hot water stored in the hot water is operated for hot water supply, the hot water in the hot water storage tank 4 and tap water supplied from the water supply pipe 5 through the pressure reducing valve 6 are mixed by the mixing valve 20 to a predetermined temperature. The hot water supply terminal 22 such as a faucet or a bath is supplied with hot water through the hot water supply pipe 21.

At this time, the water supply pipe 5 is provided with a pressure reducing valve 6 for reducing the pressure so that the pressure of the water supply pressure is not applied to the hot water storage tank 4, and the pressure is reduced to about 280 kPa. Accordingly, when the hot water supply terminal 22 is turned on and off, a pressure of about 20 to 60 kPa and a set pressure of the pressure reducing valve 6 of 280 kPa are repeatedly applied to the hot water storage tank 4. Further, the pressure 33 until the pressure relief valve 9 is opened when the temperature in the hot water storage tank 4 rises and the internal pressure increases.
0 kPa is applied to the hot water storage tank 4.

  Therefore, the body plate 15 of the hot water storage tank 4 repeats expansion and contraction at the center with the joint 15a between the upper plate 14 and the body plate 15 Tig welded and the joint 15b between the lower plate 16 and the body plate 15 as fulcrums. It will be. At the same time, the upper plate 14 and the lower plate 16 also repeat the expansion / contraction although it is the top. At that time, stress is also applied to the pipe connecting portions 14d, 14e, 14f, 16d, 16e, and 16f, and the highest is the root of the portion subjected to burring.

  On the other hand, in the upper plate 14 shown in FIGS. 4 and 5, of the pipe connecting portions 14d, 14e, and 14f, not only the central portion 14d, but 14e and 14f are elliptical portions of the top portion 14a. On the other hand, the shape processed in the normal direction prevents the thickness of the base portion from being reduced, and ensures strength.

  As described above, the strength of the upper plate 14, the body plate 15, and the lower plate 16 is increased, so that the hot water storage tank 4 having excellent durability can be obtained without causing cracks. Therefore, the set pressure of the pressure reducing valve 6 can be set high, the shower pressure that is a hot water supply terminal can be increased, and the use of the shower is greatly improved, and the hot water supply pressure is increased. As a result, bath water supply to the third floor becomes possible, faucet hot water supply to the third floor becomes possible, and the usability becomes very good.

  When the pressure reducing valve 6 fails, the 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 tank up to that pressure. Although this set pressure is higher than the set pressure of the pressure reducing valve 6, no abnormality is caused by improving the strength of the hot water storage tank 4.

  When the pressure reducing valve 6 and the pressure relief safety valve 12 are provided, the pressure above the pressure reducing valve 6 and the pressure relief safety valve 12 is not applied to the hot water storage tank 4. However, if it is 0.3 MPa or less, it is required that there be no water leakage, deformation, breakage or other abnormalities by applying a hydrostatic pressure of 0.3 MPa. If it is above, it can be interpreted that there is no need for water leakage, deformation, breakage and other abnormalities at 1.75 MPa. This time, assuming that the setting of the pressure relief safety valve 12 exceeds 0.3 MPa, apply a hydrostatic pressure of 1.75 MPa, there is no water leakage, deformation, breakage and other abnormalities, And shall be.

  On the other hand, by taking the measures as described above, it is satisfied that there is no water leakage, deformation, breakage or other abnormality.

  Table 1 shows the internal pressure taken on the X-axis and the Mises stress of the top 5a taken on the Y-axis, but the conventional top 5a has an elliptical shape compared to the R-shaped one. It can be seen that the stress can be reduced. However, if the elliptical shape is made close to a spherical surface, the tank capacity of the hot water storage tank 4 is reduced. On the other hand, the top 5a has an elliptical shape in which the long side B is 1.1 to 1.3 times and the short side C is 0.4 to 0.6 times the diameter A of the hemispherical plane circle, When the chamfered shape 14c of the elliptical contact portion between the outer peripheral vertical portion 14b and the top portion 14a is R80 or more, the stress can be reduced while the tank capacity is rather increased.

  In addition, when hot water supply and OFF are repeated at a hot water supply terminal 22 (such as a faucet), 0 (zero) pressure and the set pressure of the pressure reducing valve 6 or the pressure relief valve 9 are repeatedly applied to the hot water storage tank 4 as described above. It will be. Repeated load is applied. In order to ensure durability under such conditions, the durability of the body plate 15 can be improved by making the thickness of the body plate 15 the same as or thicker than that of the upper plate 14 and the lower plate 16.

  If it sees in the whole hot water storage tank, the location with the highest stress is a junction part of the lower board 16 and the trunk | drum 15. The joint between the lower plate 16 and the body plate 15 is as shown in FIG. 6, and the lower plate 16 and the body plate 15 are integrated at the joint 15b. When pressure P is applied from the inside, the lower plate 16 formed by drawing a stainless steel plate having corrosion resistance does not deform outward because of its high strength.

  On the other hand, the body plate 15 in which the flat plate is formed into a cylindrical shape by roll processing has a shape that bulges outward with the joint portion 15b as a fulcrum, and the stress of the fulcrum 15b is the highest. For this reason, cracks in the Tig welded portion occur at the joint 15b due to repeated loads. On the other hand, by making the plate thickness of the body plate 15 the same as or thicker than that of the upper plate 14 and the lower plate 16, the strength of the body plate 15 is increased, deformation due to the pressure P is reduced, and stress is also reduced. Durability will increase.

Table 2 shows a case where strain gauges are attached to the body plate 15 and the lower plate 16 and the hot water supply terminal is turned on and off. The amount of strain is measured. The smaller the amount of distortion, which is the displacement of the body plate 15 and the lower plate 16, is stronger in terms of durability, and in particular, the smaller the displacement difference between the body plate 15 and the lower plate 16, the better. It is considered that the plate 15 and the lower plate 16 have the same thickness, but the thinner the lower plate, the smaller the displacement difference, and the better the resistance to repeated loads. However, if the plate thickness is increased, the cost will naturally increase. Therefore, if there is no problem in terms of quality, it is more realistic to select the same thickness for the body plate 15 and the lower plate 16. Although the lower plate 16 and the trunk plate 15 have been described here, the same concept applies to the upper plate 14 and the trunk plate 15.

  Of the pipe connection portions 14d, 14e, and 14f of the upper plate 14, not only 14d at the center, but 14e and 14f are processed in the normal direction with respect to the elliptical portion of the top portion 14a. is there. As shown in an enlarged view in FIG. 7, a conventional pipe connection part for connecting water and hot water supply pipes is provided with a horizontal processing part 14h on the top part 14a of the upper plate 14. It was.

  Therefore, the horizontal processing portion 14h is provided with a concave portion 14i on the inner side and a convex portion 14j on the outer side, and there is a horizontal processing portion 14h between them, and a pipe socket is connected to a pipe opening 14k in the horizontal processing portion 14h. 19 was welded and integrated.

  This is to perform hole processing in the vertical direction when processing the pipe connection portion. However, since such a horizontal processing portion 14h is provided, the thickness of the concave portions 14i and the convex portions 14j is reduced. Therefore, it has become weak with respect to the repeated load which has been described so far. In particular, the inflection points of the concave portion 14i and the convex portion 14j are the weakest.

  On the other hand, as shown in FIG. 4 and FIG. 5, if processed in the normal direction of the top portion 14 a, the thickness will not be reduced, and the durability will be greatly improved. The plate thickness of the upper plate 14 or the lower plate 16 can be reduced, and the cost can be reduced.

  Table 3 shows the value of the maximum stress location of the pipe connection portion in various specifications when a pressure of 340 kPa is applied from the inside. From the top, as shown in FIG. 7, as in the conventional case, when the horizontal processing portion 14h is provided and the burring shape of the pipe connection portion is provided at the substantially central portion thereof, when the plate thickness of the upper plate is t1.0, The second stage has the same specifications and the plate thickness is t1.2, and the third stage has a burring hole in the pipe connection portion in the normal direction in the elliptical shape 14a at the top, and the plate thickness is t1.0. The stage is the case of t1.2 in the same specification.

  In addition, the pipe connection part is a pipe connection part 14e located at least 50 mm inward from the intersection of the central part 14d of the elliptical shape 14a at the top part and the elliptical shape 14a and the chamfering part 14c at the top part, and the elliptical shape at the top part. The value of the pipe connection port 14m located within 50 mm from the intersection of 14a and the chamfered shape 14c is shown. Further, the root R of the burring hole in the pipe connection portion is changed to R0.5, R1.0, and R1.5.

  As can be seen, the Mises stress value is high when the horizontal machining portion 14h is provided, and the value is low when machining is performed in the normal direction without the horizontal machining portion. Further, when viewed from the plate thickness, the thicker one is lower, and when viewed from the root R, the larger R is lower. Moreover, if it sees by 14e and 14m, 14e is low. Furthermore, the horizontal processing part 14h is provided, and t1.0 processed in the normal direction has a surface where the Mises stress is lower than the case of t1.2, and the cost rationalization effect can be enhanced.

  As described above, the pipe connection portion is provided on the surface of the elliptical shape 14a at the top, and this pipe connection portion is processed in the normal direction with respect to the elliptical shape 14a, and the positions thereof are the elliptical shape 14 at the top, the chamfered shape, and the elliptical shape. It can be seen that setting the distance inward by 50 mm or more from the crossing point has a high effect of reducing Mises stress, and thereby has a cost rationalization effect by reducing the plate thickness. The above has been described with respect to the upper plate 14, but the same applies to the lower plate 16. As described above, it is possible to provide a hot water storage tank of a hot water supply apparatus that is excellent in pressure resistance, durability, and cost reduction.

Further, the fact that the legs 17 for supporting the hot water storage tank 4 or the leg mounting brackets 18 for holding the legs are attached to the body plate 15 of the hot water storage tank 4 is a lower part in which ductility is reduced and ductility is reduced by work hardening. It is possible to prevent the occurrence of cracks from the welded portion, which may occur when attached to the plate 16, and to increase the strength by welding to the cylindrical plate 15 which is cylindrical and strong in the circumferential direction. In order to increase the shower pressure by increasing the set pressure of the pressure reducing valve 6 and the pressure relief valve 9 and thereby increase the momentum of the shower, or to supply hot water in high places such as hot water supply on the third floor in a three-story house It becomes possible to increase the hot water supply pressure, and the usability is greatly improved.

  By the way, as a method for increasing the shower pressure, there is a method using a pressurizing pump. This is to increase the shower pressure by providing a pressure pump on the outlet side of the hot water supply and increasing the hot water supply pressure. However, there are also problems such as that construction is required at the time of installation and the price of the pressure pump is increased.

  On the other hand, increasing the strength of the hot water storage tank 4 and increasing the set pressure of the pressure reducing valve 6 and the pressure relief safety valve 12 means that the pressure of the bath circuit 23 also increases, and consequently the hot water time of the bath Can be greatly shortened.

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

Front view of hot water supply apparatus in Embodiment 1 of the present invention Circuit diagram of the water heater (A) Top view of the hot water storage tank of the hot water supply device (b) Side view of the hot water storage tank of the hot water supply device Detailed cross-sectional view of the hot water storage tank of the water heater Other detailed enlarged views of the hot water storage tank of the water heater Load schematic diagram of the hot water supply system Detailed cross-sectional view of a hot water storage tank of a conventional water heater Sectional view of a conventional water heater

DESCRIPTION OF SYMBOLS 1 Hot water storage tank unit of hot water supply apparatus 2 Heat pump unit 3a, 3b Water piping 4 Hot water storage tank 5 Water supply pipe 6 Pressure reducing valve 7 Water pump 8 Control P board 9 Pressure relief safety valve 10 Compressor 11 Radiator 12 Air-refrigerant heat exchanger 13 Blower Fan 14 Upper plate 14a Top portion 14b Peripheral vertical portion 14c Chamfered shape 14d, 14e, 14f Pipe connecting portion 14g Horizontally processed portion 14h Recessed portion 14i Convex portion 14j Piping opening portion 15 Body plate 16 Lower plate 16d, 16e, 16f Piping connecting portion 17 Leg 18 Leg bracket 19 Piping socket 20 Mixing valve 21 Hot water pipe 22 Hot water terminal

Claims (4)

Hot water heated to an arbitrary temperature using a heating means is stored, and approximately hemispherical upper and lower plates are disposed above and below a substantially cylindrical body plate, respectively. The vertical cross-sectional shape of the top part of the top plate is an elliptical shape having a long side 1.1 to 1.3 times and a short side 0.4 to 0.6 times the diameter of a substantially hemispherical plane circle, A pipe connecting portion provided on the lower plate is integrally formed or connected in the normal direction of the elliptical surface of the upper plate and / or the lower plate, and the substantially hemispherical outer periphery substantially vertical portion and the elliptical shape are The chamfered shape of the contacted part is a part of a circular shape with a radius of 80 mm or more, and has a water supply part for supplying tap water and a pressure reducing valve for reducing the water supply pressure to the water supply part, and the setting of the pressure reducing valve A hot water storage tank of a hot water supply apparatus, wherein the pressure is 0.25 MPa or more . The hot water storage tank of the hot water supply apparatus according to claim 1, wherein the thickness of the body plate is equal to or greater than the thicknesses of the upper plate and the lower plate. The hot water supply device according to claim 1 or 2, wherein the center position of the pipe connecting portion is located at least 50 mm inward from the intersection of the elliptical portion and the chamfered portion at the top of the upper plate and the lower plate. Hot water storage tank. The hot water storage tank of the hot water supply device according to any one of claims 1 to 3 , and a heating unit formed by sequentially connecting a compressor, a water-refrigerant heat exchanger, a decompression unit, and an air-refrigerant heat exchanger. A heat pump water heater characterized by comprising.