Hot water storage tank and method for modifying a hot water storage tank

Abstract

To provide a hot water storage tank that is easy to maintain. [Solution] The hot water storage tank 11 comprises a tank body 12 in which hot water is stored, a heat exchanger 13 that heats the hot water via a heat transfer plate 13C with steam, and a circulation pipe 14 having a supply pipe 14A that guides hot water from inside the tank body 12 to the heat exchanger, and a return pipe 14B that guides hot water from the heat exchanger 13 back into the tank body 12. Preferably, it comprises a pump 17 that sends hot water from the supply tank body 12 to the heat exchanger 13, and a supply water pipe 20 connected to the supply pipe 14A between the tank body 12 and the pump 17.

Description

Technical Field

[0001] This specification discloses a hot water storage tank and a method for modifying the hot water storage tank.

Background Art

[0002] Japanese Utility Model Laid-Open No. 56-144978 discloses a hot water storage tank in which a heat exchanger is disposed inside a pressure vessel. FIG. 3 shows an example of a hot water storage tank 1 in which a heat exchanger 3 is similarly disposed inside a tank body 2. In this hot water storage tank 1, hot water is stored in the tank body 2. The heat exchanger 3 has a steam pipe 3A through which pressurized steam flows. The tank body 2 is watertight. Pressurized steam is passed through the steam pipe 3A inside the tank body 2. The hot water inside the tank body 2 is heated by this pressurized steam.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

[0007] In this hot water storage tank, the tank body does not constitute a pressure vessel. This hot water storage tank is easy to maintain. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is a conceptual diagram of a hot water storage tank according to one embodiment. [Figure 2] Figure 2 is a perspective view of the discharge pipe provided in the hot water storage tank shown in Figure 2. [Figure 3] Figure 3 is a conceptual diagram showing an example of a conventional hot water storage tank. [Modes for carrying out the invention]

[0009] Preferred embodiments will be described in detail below, with reference to drawings as appropriate.

[0010] Figure 1 shows a hot water storage tank 11. This hot water storage tank 11 is used, for example, in a central hot water supply system for accommodation facilities. The hot water storage tank 11 comprises a tank body 12 in which hot water is stored, a heat exchanger 13 for heating the hot water in the tank body 12, a circulation pipe 14 located between the tank body 12 and the heat exchanger 13, and a discharge pipe 15 for releasing hot water from the circulation pipe 14 into the tank body 12.

[0011] Furthermore, the hot water storage tank 11 is equipped with a temperature sensor 16 for detecting the temperature of the hot water in the tank body 12. The hot water storage tank 11 is equipped with a pump 17 for circulating the hot water in the circulation piping 14. The hot water storage tank 11 is equipped with a steam piping 18 for supplying steam to the heat exchanger 13 and recovering steam and drain from the heat exchanger 13, and a switching valve 19 attached to the steam piping 18 for supplying and stopping steam. The hot water storage tank 11 is equipped with a replenishment water piping 20 connected to the circulation piping 14 for replenishing water. The hot water storage tank 11 is equipped with a switching valve 21 attached to the replenishment water piping 20 for supplying and stopping replenishment water. The hot water storage tank 11 is equipped with a controller 22 that receives detection data from the temperature sensor 16 and controls the heat exchanger 13, the pump 17, and the switching valve 19.

[0012] The tank body 12 is watertight. The tank body 12 has a supply port 12A for sending the stored hot water to equipment within the facility, and a hot water pipe connection port 12B to the tank body 12. The tank body 12 has a flange 12C with an opening to which the circulation piping 14 is attached. The tank body 12 has a fusible plug 12D to release high-pressure gas in case of abnormal temperature or pressure rises. For example, in a central hot water supply system for accommodation facilities, the tank body 12 has a large internal volume to supply hot water to the entire facility.

[0013] The heat exchanger 13 has a heated passage 13A connected to the circulation pipe 14, a heated passage 13B connected to the steam pipe 18, and heat transfer plates 13C separating the heated passage 13A and the heated passage 13B. The heat exchanger 13 is, for example, a plate heat exchanger. The number of heat transfer plates 13C arranged in this heat exchanger 13 can be changed. By changing the number of heat transfer plates 13C and thereby changing the number of heated passages 13A and heated passages 13B, the heating capacity of the heat exchanger 13 can be increased or decreased.

[0014] The circulation piping 14 includes a forward pipe 14A that guides hot water from the tank body 12 to the heated passage 13A of the heat exchanger 13, and a return pipe 14B that guides hot water from the heated passage 13A of the heat exchanger 13 back to the tank body 12. The circulation piping 14 has a flange 14C as a mounting part for attaching the circulation piping 14 to the tank body 12. The circulation piping 14 is attached to the flange 12C of the tank body 12 with the flange 14C. The circulation piping 14 is fixed to the tank body 12 with the inlet of the forward pipe 14A and the outlet of the return pipe 14B located inside the tank body 12.

[0015] Pump 17 is connected to the supply pipe 14A. Replenishment water pipe 20 is connected to the supply pipe 14A between the tank body 12 and the pump 17. A discharge pipe 15 is connected to the outlet of the return pipe 14B. The discharge pipe 15 is located inside the tank body 12. The discharge pipe 15 may be integrally molded with the return pipe 14B.

[0016] Figure 2 shows the discharge pipe 15 together with a portion of the return pipe 14B. The discharge pipe 15 has a hollow pipe shape with a closed end face. The discharge pipe 15 has a plurality of holes 15A that are located in different positions and have different opening directions in the outer circumference direction. The discharge pipe 15 also has a plurality of holes 15A that are located in different positions in the longitudinal direction. The plurality of holes 15A only need to be located in different positions and have different opening directions in the outer circumference direction and in the longitudinal direction, and the spacing and opening directions of the holes in the outer circumference and longitudinal direction are not particularly limited.

[0017] In Figure 2, the double arrow Dm represents the inner diameter of the vent pipe 15. The symbol Sm represents the diameter area of ​​the vent pipe 15. The double arrow Da represents the inner diameter of the hole 15A. The symbol Sa represents the opening area of ​​the hole 15A. The total opening area of ​​the hole 15A is calculated by multiplying the opening area Sa by the number of holes 15A N (where N is a natural number greater than or equal to 2). In this vent pipe 15, the total opening area N·Sa is smaller than the diameter area Sm of the vent pipe 15. Furthermore, in this vent pipe 15, the total opening area N·Sa of the hole 15A is smaller than the diameter area of ​​the return pipe 14B.

[0018] The hot water storage tank 11 includes a heat exchanger 13 that heats water via a heat transfer plate 13C with steam. The hot water storage tank 11 includes a circulation pipe 14 having a forward pipe 14A that guides water from inside the tank body 12 to the heat exchanger 13 and a return pipe 14B that guides water from the heat exchanger 13 into the tank body 12. In this hot water storage tank 11, the heat exchanger 13 is located outside the tank body 12. Even if the heat exchanger 13 through which pressurized steam flows is damaged, the tank body 12 does not receive the pressure of the steam. This tank body 12 does not correspond to a pressure vessel. This tank body 12 is easy to manage. Repair of this tank body 12 does not require procedures at a government office.

[0019] The hot water storage tank 11 includes a pump 17 that sends water from the tank body 12 to the heat exchanger 13 through the forward pipe 14A and a makeup water pipe 20 connected to the forward pipe 14A between the tank body 12 and the pump 17. Even if water is sent out from the tank body 12, the makeup water pipe 20 can prevent the tank body 12 from becoming negative pressure. It is possible to prevent the tank body 12 from being damaged by negative pressure.

[0020] The hot water storage tank 11 includes a diffuser pipe 15 attached to the outlet of the return pipe 14B. The diffuser pipe 15 is located inside the tank body 12 and has a plurality of holes 15A on the outer periphery with different opening directions. By discharging water from the holes 15A of the diffuser pipe 15 into the tank body 12, the water inside the tank body 12 is stirred. The hot water storage tank 11 can equalize the temperature of the water inside the tank body 12.

[0021] In this diffuser pipe 15, the total opening area N·Sa of the holes 15A is smaller than the diameter area Sm of the diffuser pipe 15. Thereby, the diffuser pipe 15 can reduce the difference between the amount of water discharged from the holes 15A far from the outlet of the return pipe 14B and the amount of water discharged from the holes 15A close to the outlet of the return pipe 14B. Therefore, in the diffuser pipe 15, it is preferable that the total opening area N·Sa is smaller than the diameter area Sm.

[0022] This hot water storage tank 11 can be obtained by modifying a storage tank in which a steam-based heat exchanger 3, as shown in Figure 3, is attached to the tank body 12. In this modification method, a circulation pipe 14 is prepared. The heat exchanger 3 is removed from the flange 12C of the tank body 12. The inlet of the supply pipe 14A and the outlet of the return pipe 14B are positioned inside the tank body 12, and the circulation pipe 14 is attached to the flange 12C of the tank body 12. This modification method can change a tank body 12 that corresponds to a pressure vessel into a tank body 12 that does not correspond to a pressure vessel.

[0023] Repairing the conventional hot water storage tank 1 shown in Figure 3 requires government procedures because the tank body 2 is classified as a Class 1 pressure vessel, and modifications to the hot water storage tank 1 are restricted. Repairing the tank body 2 when it deteriorates over time is time-consuming. As mentioned above, by changing the tank body 12, which is classified as a Class 1 pressure vessel, to a tank body 12 that is not classified as a pressure vessel, the effort required for repairs and modifications can be reduced. This modification method can shorten the construction period and reduce construction costs.

[0024] Internal volume is 0.04 m³ 3 A tank body 12 exceeding this size qualifies as a Class 1 pressure vessel if it meets certain requirements. Therefore, in this modification method, the internal volume is 0.04 m³. 3 This is particularly effective for modifying the tank body 12 beyond a certain point.

[0025] [Disclosure items] Each of the following items discloses a preferred embodiment.

[0026] [Item 1] The main tank that can hold hot water, A heat exchanger that heats the hot water via a heat transfer plate using steam, And, A circulation channel having a forward channel for guiding the hot water from the tank body to the heat exchanger, and a return channel for guiding the hot water from the heat exchanger back into the tank body, A hot water storage tank equipped with a hot water storage tank.

[0027] [Item 2] The hot water storage tank according to item 1, comprising a pump that sends hot water from the tank body to the heat exchanger in the forward flow path, and a supply water flow path connected to the forward flow path between the tank body and the pump.

[0028] [Item 3] The hot water storage tank according to item 1 or 2, comprising a discharge pipe attached to the outlet of the return flow path, located inside the tank body, and having a plurality of holes on its outer circumference with different opening directions.

[0029] [Item 4] A method for modifying a hot water storage tank, comprising a tank body and a steam heat exchanger having steam piping, wherein the steam piping is positioned inside the tank body and the steam heat exchanger is attached to the tank body, A circulation channel is prepared having a forward channel for guiding the hot water from the tank body to another heat exchanger, and a return channel for guiding the hot water from the other heat exchanger back into the tank body. Remove the steam heat exchanger from the tank body, A method for modifying a hot water storage tank, comprising positioning the inlet of the forward flow path and the outlet of the return flow path within the tank body, and attaching the circulation flow path to the tank body. [Explanation of symbols]

[0030] 11. Hot water storage tank 12...tank body 12C...Flange (mounting part) 13...heat exchanger 13C Heat Transfer Plate 14. Circulation piping (circulation channel) 14A... Supply piping (supply path) 14B...Return piping (return channel) 15. Dispersion tube 15A...hole 17. Pump 20...Makeup water piping (makeup water flow path)

Claims

1. The main tank that can hold hot water, A heat exchanger that heats the hot water via a heat transfer plate using steam, And, A circulation channel having a forward channel for guiding the hot water from the tank body to the heat exchanger, and a return channel for guiding the hot water from the heat exchanger back into the tank body, A hot water storage tank equipped with a hot water storage tank.

2. The hot water storage tank according to claim 1, further comprising a pump that sends hot water from the tank body to the heat exchanger in the forward flow path, and a supply water flow path connected to the forward flow path between the tank body and the pump.

3. The hot water storage tank according to claim 1 or 2, further comprising a discharge pipe attached to the outlet of the return flow channel, located inside the tank body, and having a plurality of holes on its outer circumference with different opening directions.

4. A method for modifying a hot water storage tank, comprising a tank body and a steam heat exchanger having steam piping, wherein the steam piping is positioned inside the tank body and the steam heat exchanger is attached to the tank body, A circulation channel is prepared having a forward channel for guiding the hot water from the tank body to another heat exchanger, and a return channel for guiding the hot water from the other heat exchanger back into the tank body. Remove the steam heat exchanger from the tank body, A method for modifying a hot water storage tank, comprising positioning the inlet of the forward flow path and the outlet of the return flow path within the tank body, and attaching the circulation flow path to the tank body.

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