JP5842563B2 - Fluid heating device and electric water heater - Google Patents

Description

  The present invention relates to a fluid heating device having an overheat prevention mechanism and an electric water heater provided with the fluid heating device.

  For example, Patent Document 1 discloses an instantaneous heating device that instantaneously heats a fluid with electric power. In such a fluid heating device, the heater continues to be energized in the air heating, that is, in a state where water is not stored in the water storage container or in a state where the amount of stored water is extremely small, and the temperature rises abnormally. It is desirable to provide a mechanism for preventing the surroundings from being overheated. In Patent Document 2, a thermal case made of a member having excellent thermal conductivity is attached so as to be in contact with the vicinity of the heater or the surface of the heater in order to prevent air blowing, and a thermal member (thermal fuse) is installed therein. ) Is proposed. When the heater is heated up abnormally, the heat-sensitive case is heated without delay so that the heater is de-energized at the initial stage when the abnormal temperature rise occurs, preventing overheating of the hot water tank and peripheral equipment. The

JP 2007-218006 A JP 2002-327961 A

  However, in the configuration of Patent Document 2, in order to detect an abnormal temperature rise of the heater, a process is required in which the heat sensitive case is heated by the heat of the heater and the temperature sensitive member is further heated. There is a delay between the occurrence of the current and the stop of energization of the heater. In particular, when the heater is energized in a state where the drain plug for discharging water in the hot water tank at one time is forgotten to be closed and overheated, between the heater and the thermal case and / or In heat transfer between the heat-sensitive case and the heat-sensitive member, processes of heat radiation and heat conduction in the air are involved, and the delay time from the occurrence of the overheat state to the detection becomes long. In addition, both a heat-sensitive case and a temperature-sensitive member are required, and material costs and manufacturing costs are required.

  In view of the above circumstances, the problem to be solved by the present invention is to provide a fluid heating apparatus having an overheat prevention mechanism that suppresses the occurrence of abnormal temperature rise and prevents emptying even when the discharge port for discharging the fluid is opened. Another object of the present invention is to provide an electric water heater without using a separate member such as a heat sensitive case.

  In order to solve the above-described problems, a fluid heating apparatus according to the present invention includes a heater that heats a fluid, and a fluid container in which the heater is provided, and the fluid container flows in fluid from a fluid supply source. An inflow port, an outflow port for allowing the fluid to flow out to the outside of the fluid container, a discharge port capable of discharging the fluid accumulated inside the fluid container to the outside, and the discharge port, A drain stopper that suppresses fluid, and a fluid residual portion in which fluid remains in the fluid container when the drain stopper is disengaged from the state where fluid is stored in the fluid container and the discharge port is opened. And at least a part of the heater is provided inside the fluid residual portion.

  Here, it is preferable that the discharge port is provided in a protruding shape at the bottom of the fluid container, and the fluid remaining portion is below the tip of the protrusion.

  Further, the discharge port is higher than the bottom of the fluid container, and can discharge the fluid in the fluid container to the outside by its own weight, and the fluid remaining portion includes a tip of the discharge port and a bottom of the fluid container. It is good to form in the space between.

  In this case, the discharge port is preferably a hollow protrusion and an opening provided at the upper end.

  Further, the heater has a hollow cylindrical heating portion having a vertical axis as a central axis, and the discharge port is provided at an upper end portion of a hollow protrusion protruding from the lower end of the heater into the cylinder of the heating portion. What is necessary is just the opening part made.

  Further, in this case, the hollow cylindrical heater has heating portions on the inner wall surface and the outer wall surface of the hollow cylinder body, and the fluid supplied from the upper end into the heater flows out from the lower end, It is preferable that the flow path be configured to be discharged from an outlet located above the heater after flowing through the heater.

  Further, the fluid heating device includes an electromagnetic valve between the inlet and the fluid supply source, and a safety device that cuts off power to the heater when the temperature in the fluid container exceeds a set value. And the safety device closes the solenoid valve and stops the flow of fluid into the fluid container after the power supply to the heater is shut off when the temperature in the fluid container exceeds a set value. There should be.

  An electric water heater according to the present invention includes the above-described fluid heating device, a water supply port that takes in water for heating, a hot water outlet that discharges heated hot water, and water that flows into the fluid heating device. A flow meter that measures the flow rate of water and a flow rate adjustment valve that adjusts the flow rate of water flowing into the fluid heating device based on the flow rate of water measured by the flow meter, and the water flow is not detected by the flow meter In this case, the gist is to cut off the energization to the heater of the fluid heating device.

  According to the fluid heating device of the present invention, the fluid remaining portion is opened even after the discharge port is opened from the state where the fluid is stored in the fluid container including the fluid remaining portion, and most of the fluid inside the fluid container is discharged. Fluid remains. At least a part of the heater is provided inside the fluid residual portion, and the fluid remaining in the fluid residual portion is heated by the heater. Therefore, even if the heater is energized in a state where the outlet is forgotten to close, the fluid residual portion The heater output is used to heat the fluid remaining in the fluid, and overheating of the inside of the fluid container and peripheral devices can be suppressed. Furthermore, it is not necessary to use a member having excellent thermal conductivity, such as a heat sensitive case, as a constituent member of the overheat prevention mechanism, and the cost can be suppressed.

  Here, if the discharge port is provided in a protruding shape at the bottom of the fluid container, and the fluid remaining part is below the tip of the protrusion, the fluid is discharged downward from the bottom surface of the fluid container. The degree of freedom of incorporation into another device such as a vessel increases.

  Furthermore, when the discharge port is higher than the bottom of the fluid container and the fluid residual part is formed in the space between the tip of the discharge port and the bottom of the fluid container, the water in the fluid residual part is heated by the heater. The heat can be dissipated to the outside through the bottom of the fluid container, so that overheating can be effectively prevented.

  In this case, when the discharge port is a hollow protrusion and the opening is provided at the upper end, the configuration of the bottom of the fluid container provided with the discharge port is simplified, and the fluid remaining portion does not have to be separately configured. Since the space between the discharge port and the fluid container bottom inevitably becomes a fluid residual portion, the manufacturing cost can be reduced.

  Furthermore, if the heater has a hollow cylindrical heating section with the vertical axis as the central axis, and the discharge port is provided at the upper end of the hollow protrusion protruding into the heater from the lower end of the heater, the entire fluid heating apparatus It is possible to design even in a narrow space.

  Furthermore, the hollow cylindrical heater has heating portions on the inner wall surface and the outer wall surface, and the fluid supplied from the upper end into the hollow cylindrical heater flows out from the lower end and flows outside the heater, and then the heater If the flow path is configured so as to be discharged from the outlet located above, the fluid is heated both inside and outside and supplied from the outlet over almost the entire length of the heating portion of the heater. Therefore, the fluid is heated with high efficiency. Further, as another effect that the flow path is configured as described above, since the fluid circulation direction is the vertical direction, an air pocket is not formed in the fluid container unlike the case of the substantially horizontal direction. There is an advantage. Therefore, heat insulation due to the air pool does not occur, and the temperature of the fluid supplied from the outlet is unlikely to vary. Further, while the fluid is flowing along the flow path, the fluid remaining in the fluid residual portion is constantly replaced, so that cleanliness is maintained.

  The fluid heating device includes a solenoid valve between the inlet and the fluid supply source, and a safety device that shuts off the power to the heater when the temperature in the fluid container exceeds a set value. If the temperature inside the container exceeds the set value, the heater is cut off, and if the temperature of the fluid vaporized by the heating of the fluid in the fluid residual portion reaches a preset value, the safety device The power supply to the heater is cut off. As a result, the fluid in the fluid container is exhausted to the outside of the fluid container when the discharge port is opened without having a fluid residual portion, and the heat of the heater is only caused by heat radiation and heat conduction in the air. As compared with the case where the temperature is not transmitted to the temperature sensing unit, it is possible to detect an abnormal temperature rise inside the fluid heating device due to airing earlier. Therefore, as described above, by heating the fluid in the fluid remaining portion, the output of the heater is consumed, and in addition to preventing overheating of the fluid container and peripheral devices, the energization to the heater is stopped early. However, it is possible to effectively prevent airing.

  Moreover, since the electric water heater concerning this invention is equipped with the fluid heating apparatus which has said effect, it can prevent hot airing reliably and can supply warm water. Furthermore, even when no water flow is detected by the flow meter, the energization to the heater is cut off, so that the air-spreading is prevented by a double mechanism, and safety is further enhanced.

It is sectional drawing of the fluid heating apparatus concerning one Embodiment of this invention. It is the figure which simplified sectional drawing of the fluid heating apparatus of FIG. It is an enlarged view of the bottom face vicinity of the fluid heating apparatus of FIG. 1, (a) shows the state which closed the discharge port and stored water in the fluid container, (b) shows the state which opened the discharge port. It is a front view of the electric water heater concerning one embodiment of the present invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the following description, the vertical direction or the vertical direction refers to the vertical direction, and the horizontal direction refers to the horizontal direction.

  1 and 2 are longitudinal sectional views of a fluid heating apparatus according to an embodiment of the present invention. Hereinafter, the fluid is described as water, but the type of fluid is not limited.

  In the fluid heating apparatus 1 according to the present embodiment, a heater 12 that can heat water by energization is inserted into the fluid container 10. The fluid container 10 includes an inlet 13 through which water flows in from a water source such as a water supply and an outlet 14 through which hot water flows out. The low-temperature water supplied from the water source is heated by the heater 12, and the hot water is continuously supplied to the outside. Can be supplied to. In addition, the fluid container 10 includes a discharge port 15 that can be opened and closed by a drain plug 19. For the convenience of internal maintenance and prevention of breakage of the fluid container 10 due to water freezing in winter, the fluid container 10 Water can be discharged. Further, although not shown, an electromagnetic valve 17 is provided between the inlet 13 and the water source, and the supply of water to the inlet 13 is controlled by opening and closing.

  The fluid heating device 1 further includes a safety device 16. The safety device 16 receives a temperature sensing unit 16a that measures the temperature in the fluid container 10 and a temperature signal output from the temperature sensing unit 16a, and when the measured temperature exceeds a preset temperature, The controller 16b is configured to stop energization and stop water flow by shutting off the electromagnetic valve 17. If the heater 12 is not stopped when an abnormal temperature rise occurs and the fluid heating device 1 is overheated, the fluid container 10 may be damaged, equipment such as the safety device 16 may be broken, or a fire may occur. ,It is a danger.

  Next, each component of the fluid heating device 1 will be described in detail.

  The heater 12 may be anything as long as it is a highly insulating heater capable of heating water with electric power, but the entire fluid heating device 1 may be designed to be small, and water will flow in the vertical direction as will be described later. Considering the construction of the flow path, etc., a ceramic heater having a hollow cylindrical shape for the heating part 12b is suitable. Moreover, since heating efficiency improves, so that the area which the heating part 12b contacts with water is large, it is desirable to have a heating part in both the inner wall surface and outer wall surface of a hollow cylindrical ceramic heater. The heater 12 has a flange portion 12a for fixing to the fluid container 10 in addition to the heating portion 12b.

  The fluid container 10 may have any shape as long as it accommodates the heater 12 and allows water to flow through the generated gap, but the portion that accommodates the heater 12 has an outer diameter of the cylindrical portion of the heater 12. Any substantially cylindrical container having a larger inner diameter may be used. The heater 12 is attached to the upper end portion of the fluid container 10 at the flange portion 12a so that the central axis of the cylindrical portion is in the vertical direction. The lower end of the heater 12 serves as a discharge port 12c through which water is discharged from the inside of the cylindrical body. However, since the tip 12d of the discharge port 12c is not in contact with the bottom surface of the fluid container 10, the bottom of the fluid container 10 Water can flow from the inside of the cylindrical portion of the heater 12 to the outside.

  The inlet 13 is an opening at the upper end of the heater 12, and water flows from the water source through the inlet 13 into the cylindrical body of the heater 12. The space between the outer wall of the heater 12 and the fluid container 10 and the inflow port 13 are isolated by the flange portion 12a, and the water supplied from the water source directly passes into the space outside the heater without passing through the inside of the cylindrical body of the heater 12. There is no inflow.

  The outlet 14 is an opening provided in the upper part of the fluid container 10 and is connected to the space between the outer wall surface of the heater 12 and the inner wall surface of the fluid container 10. The higher the position of the outlet 14, the longer the water passage described below, and the water heating efficiency is improved.

  Water entering from the inlet 13 at the upper end of the heater 12 flows downward in the cylindrical body of the heater 12 and reaches the discharge port 12 c at the lower end of the heater 12. The water then moves from the tip 12d of the discharge port 12c to a space between the outer wall surface of the data 12 and the outer wall of the fluid container 10, and flows upward from the bottom of the fluid container 10 toward the outlet port 14. Since water is heated in contact with the wall surface of the heater 12 while flowing from the top to the bottom of the heater 12 and while flowing from the bottom to the top of the heater 12, even if the total length of the heater 12 is short, the water is high. Water can be heated with efficiency.

  The heater 12 is installed so that the central axis is in the vertical direction and the tip 12d of the discharge port 12c is not in contact with the bottom surface of the fluid container 10, the inlet 13 is provided at the upper end of the heater 12, and the outlet 14 is provided. By providing it on the outside of the heater 12 and above the fluid container 10, a flow path through which water flows in the vertical direction is formed as described above. Also in Patent Document 1, a cylindrical heater is inserted into a hot water supply tank as in the present embodiment, and the fluid supplied from one side into the cylinder of the heater flows out from the other side, and the outer peripheral surface of the heater After flowing between the inner peripheral surfaces of the hot water tank, the flow path is configured to be discharged from the outlet of the hot water tank located above the heater, but unlike this embodiment, the hot water tank and the heater are sideways. It is installed at a close angle, and the flow path is in a direction close to the side. As described above, when the flow path is not in the vertical direction, even if the flow path is filled with water, an air pocket in which air bubbles collect particularly at the corners of the internal structure of the hot water tank is likely to occur. Since the air pool acts as a heat insulating material, the heat of the heater is not transmitted uniformly to the water in the flow path, and the temperature of the hot water supplied from the hot water supply tank outlet is likely to fluctuate. On the other hand, if the flow path is formed in the vertical direction as in this embodiment, when the flow path is filled with water, no air pool is generated in the middle of the flow path. Therefore, the temperature of the hot water supplied from the outlet 14 is easily stabilized.

  The safety device 16 may be any device capable of detecting the temperature inside the fluid container 10 and shutting off the energization of the heater 12 and the solenoid valve 17 as long as the temperature exceeds a set value. A temperature sensitive reed switch, a thermostat, etc. can be illustrated. The temperature-sensitive reed switch is excellent in terms of simplicity. When using a temperature-sensitive reed switch, electrical connection may be made so that the energization circuit to the heater 12 is cut off when the temperature reaches the operating temperature or higher. In addition, a so-called normally closed type that opens the valve only while current is supplied is used as the solenoid valve 17. Similarly, when the temperature reaches the operating temperature or higher, the energization to the solenoid valve 17 is cut off. Thus, electrical connection may be performed. In addition, since it is necessary to eliminate the overheat state as soon as possible after the overheat state occurs, it is better to stop the energization to the heater 12 immediately after detecting the abnormal temperature rise. Since the more water is present in the fluid container 10 including the part 11, the electromagnetic valve 17 is desirably shut off after the current is not shut off.

  The temperature sensing unit 16a of the safety device 16 may be provided anywhere as long as the temperature inside the fluid container 10 can be detected. However, if the temperature sensing unit 16a is provided in the vicinity of the outflow port 14, the temperature of the hot water supplied from the outflow port 14 is adjusted. It can be used simultaneously for the purpose of measuring and adjusting the output of the heater 12 so as to achieve an appropriate temperature.

  In the present embodiment, the fluid remaining portion 11 is simply formed by the configuration of the discharge port 15. A hollow protrusion 18 protrudes upward, that is, toward the inside of the fluid container 10 on the bottom surface of the fluid container 10. The tip 18 a of the protrusion 18 is opened, and the opening serves as the discharge port 15. The discharge port 15 communicates with the outside of the fluid container 10 through the hollow portion of the protrusion 18 and can discharge the water in the fluid container 10 to the outside only by its own weight. Except when discharging water to the outside of the fluid container 10, the downstream of the discharge port 15 may be closed by the drain plug 19. The drain plug 19 may be any detachable one that can reliably block the discharge port 15, but can be exemplified by a type in which the downstream of the discharge port 15 is blocked by a screw.

  If the discharge port 15 is provided as a simple opening on the flat bottom surface of the fluid container 10, there is no fluid residual portion 11, and when the discharge port 15 is opened, the water stored in the fluid container 10 is All flow out according to gravity. Even if water continues to be supplied from the inflow port 13, the water does not stay inside the fluid container 10 and continues to flow out from the discharge port 15. As described above, when the heater 12 is energized in the absence of water in the fluid container 10, the inside of the fluid heating apparatus 1 and peripheral devices are overheated by the heat of the heater 12. If the safety device 16 detects an abnormal temperature rise, the energization of the heater 12 is cut off and the overheating state is eliminated. In this case, the heat of the heater 12 is only caused by heat conduction and heat radiation in the atmosphere. Is transmitted to the temperature sensing part 16a. Since the thermal conductivity of air is very small, it takes a long time until an abnormal temperature rise is detected in the temperature sensing part 16a of the safety device 16 installed in the vicinity of the outlet 14 after the overheating state occurs. End up. In the meantime, the overheating state further proceeds.

  On the other hand, in the present embodiment, the fluid residual portion 11 is provided with the discharge port 15 of the protrusion 18 inside the discharge port 12c of the heater 12 which is a hollow cylindrical body, and a part of the inner wall 12e of the heater 12 A part of the outer wall 18b of the protrusion 18 is formed so as to face and a fluid remains. In other words, the space below the height position of the discharge port 15, that is, the lower space surrounded by the horizontal plane passing through the tip 18 a of the protrusion and the wall surface of the fluid container 10 becomes the fluid residual portion 11. When the discharge port 15 is closed by the drain plug 19 as shown in FIG. 3A and the drain plug 19 is removed from the state where the water W is present in the fluid container 10 and the discharge port 15 is opened, FIG. As shown in FIG. 5, the water W stored in the fluid residual portion 11 cannot escape from the discharge port 15 and remains in the fluid container 10.

Since the water W remaining in the fluid residual portion 11 is in contact with the heater 12 between the tip portion 18a of the protrusion 18 and the tip portion 12d of the discharge port 12c, if the heater 12 is energized in this state, The water W in the remaining part 11 is heated. Since water has a large specific heat and latent heat at the time of vaporization, when the heater is energized in this state, a part of the heat of the heater 12 is consumed to heat the water W in the fluid residual portion 11, and the fluid heating device 1 The overheating of the components and peripheral devices is suppressed. The heat of the heated water W is dissipated into the atmosphere through the bottom surface of the fluid container 10.

In addition, when the water W is heated, part of the water W becomes water vapor, and the heated water vapor fills the space above the fluid residual portion 11, so that the heat of the heater 12 is faster than that in the case where there is no water vapor. Is detected by the temperature sensing part 16a. In other words, the safety device 16 can be actuated to cut off the power to the heater 12 before the overheating state proceeds. Thus, by providing the discharge port 15 on the upper portion of the protrusion 18 installed on the bottom surface of the fluid residual portion 11, overheating can be efficiently prevented by two effects of suppression of overheating and early detection. Yes. This overheat prevention mechanism is particularly effective when the drain plug 19 is forgotten to be closed and the heater is energized and water is passed.

  Even if the safety device 16 breaks down and the energization of the heater 12 cannot be cut off due to the detection of abnormal temperature rise, if water remains in the fluid remaining portion 11, as described above. By using the heat of the heater 12 for heating the water, overheating of the components of the fluid heating device 1 and peripheral devices can be suppressed to some extent.

  As described above, once the residual fluid portion 11 is filled with water, water continues to remain in the residual fluid portion 11 even after the discharge port 15 is opened. However, the water flows from the inside of the cylindrical body of the heater to the outside. Since the fluid remaining portion 11 exists in the middle of the path, the fluid remaining portion 11 is in a state where water is circulated constantly, that is, in a state where the fluid heating device 1 is continuously used. The water remaining in the water is always replaced. Thereby, the water inside the fluid residual part 11 is kept clean.

  The larger the volume of the fluid remaining portion 11 and the surface area of the heating portion 12b of the heater 12 existing therein, the greater the effect of preventing overheating. Even if the outlet 15 is opened, the proportion of the water discharged out of the water in the fluid container 10 decreases, and it is difficult to achieve those purposes. Further, when the volume of the fluid residual portion 11 is increased, the height of the protrusion 18 is increased. However, when the volume is too high, resistance of water flow in the flow path is obtained. In consideration of these points, the volume of the fluid remaining portion 11 may be set as appropriate based on the dimensions of the heater 12 to be used. For example, when the length of the heat generating portion that can be used to heat water in the cylindrical heater 12, that is, the length of the heater 12 below the outlet 14 is 55 mm, the tip end portion 18 a of the protrusion 18 and the discharge port An example in which the length of the heater 12 between the front end portion 12d of 12c, that is, the portion located inside the fluid residual portion 11 is 8 mm can be presented.

  Next, an electric water heater 2 according to an embodiment of the present invention will be described with reference to FIG.

  The fluid heating device 1 shown in FIGS. 1 to 3 is installed in the lower right portion of the case 8. The fluid heating device 1 is installed such that the central axis of the cylindrical heater 12 is in the vertical direction, and the flow path of water is in the vertical direction.

  A water supply port 5 is installed at the upper end of the case 8 and is connected to the water supply to supply tap water into the electric water heater 2. Although not shown, a main plug that can be opened and closed may exist between the water supply and the water supply port 5.

  Water supplied from the water supply port 5 passes through the flow rate adjusting valve 3 and the flow meter 4 and is supplied to the fluid heating device 1 from the inflow port 13. The outlet 14 of the fluid heating apparatus 1 is connected to the hot water outlet 6 at the upper end of the case 8. The downstream of the hot water outlet 6 is connected to a faucet of a hand-washing machine, for example.

  The electric water heater 2 further has a power supply unit 7 and is connected to a commercial power supply. The power supply unit 7 supplies power to the heater 12, the safety device 16, the electromagnetic valve 17 and the like of the fluid heating device 1.

The flow rate adjustment valve 3 is an electromagnetic valve that can adjust the flow rate of water, and adjusts the amount of water supplied to the fluid heating device 1 based on the water flow rate detected by the flow meter 4. This water amount adjustment is performed for the purpose of preventing the inside of the fluid heating device 1 from being damaged by the load of water pressure even if there is a fluctuation in the water pressure of the tap water. The flow rate adjusting valve 3 may also serve as an electromagnetic valve 17 that is closed by the safety device 16 when an abnormal temperature rise in the fluid heating device 1 is detected.

  The flow meter 4 is, for example, a propeller type water flow meter that can detect the presence or absence of a water flow and the water flow rate, and transmits the flow rate to the safety device 16 as an electrical signal.

  If water is supplied to the heater 12 of the fluid heating apparatus 1 in a state where water is not supplied to the fluid heating apparatus 1, there is a possibility that emptying may occur. In order to prevent this, if the heater 12 is energized when no water flow is detected by the flow meter 4, the safety device 16 stops energization of the heater 12.

  On the other hand, when water continues to be supplied to the fluid heating device 1, but when the drain plug 19 is removed and the outlet 15 is opened, the flow meter 4 detects the water flow, so the flow meter 4 The energization to the heater 12 is not cut off based on the signal from. In this state, there is a possibility that overheating of the fluid heating apparatus 1 may occur. However, since water remains in the fluid remaining portion 11 of the fluid heating device 1, the temperature sensing portion 16 a of the safety device 16 quickly detects the temperature rise in the fluid heating device 1, and the safety device 16 moves to the heater 12. Shut off the power and water flow. That is, the electric water heater 2 is provided with an overheat prevention function based on two parameters, a water flow detected by the flow meter 4 and a temperature detected by the temperature sensing unit 16a of the safety device 16, and either one of the overheats is detected. Compared to the case where only the prevention mechanism is provided, the safety is high.

  As mentioned above, although embodiment of this invention was described in detail, this invention is not limited to the said embodiment at all, A various change is possible in the range which does not deviate from the summary of this invention.

DESCRIPTION OF SYMBOLS 1 Fluid heating apparatus 10 Fluid container 11 Fluid residual part 12 Heater 12a Flange part 12b Heating part 13 Inlet 14 Outlet 15 Outlet 16 Safety device 16a Temperature sensing part 16b Control part 17 Solenoid valve 18 Protrusion 19 Drain plug 2 Electric water heater 3 Flow control valve 4 Flow meter 5 Water supply port 6 Hot water outlet 7 Power supply unit 8 Case W Water

Claims (7)

A heater for heating the fluid;
A fluid container provided inside the heater,
The fluid container is
An inlet through which fluid flows from a fluid source;
An outlet for allowing fluid to flow out of the fluid container;
A discharge port capable of discharging the fluid accumulated in the fluid container to the outside;
A drain plug that engages with the outlet and suppresses the outflow of fluid;
A fluid residual portion in which fluid remains in the fluid container when the drain plug is released from the state where the fluid is stored in the fluid container and the discharge port is opened;
At least a portion of the heater is provided inside the fluid residual portion ;
The fluid outlet is a fluid heating device in which the discharge port is provided in a protruding shape at the bottom of the fluid container, and the fluid remaining portion is below the tip of the protrusion . The discharge port is higher than the bottom of the fluid container, and can discharge the fluid in the fluid container to the outside by its own weight.
The fluid heating device according to claim 1, wherein the fluid residual portion is formed in a space between a tip of the discharge port and a bottom portion of the fluid container. The outlet is a hollow protrusion, the fluid heating apparatus according to claim 1 or claim 2 which is an opening provided at the upper end. The heater has a hollow cylindrical heating section having a vertical axis as a central axis,
The fluid heating device according to claim 3 , wherein the discharge port is an opening provided at an upper end portion of a hollow protrusion protruding from a lower end of the heater into a cylinder of the heating unit. The hollow cylindrical heater has a heating portion on the inner wall surface and the outer wall surface of the hollow cylinder,
The flow path is configured so that the fluid supplied from the upper end into the heater flows out from the lower end, flows outside the heater, and then is discharged from the outlet located above the heater. The fluid heating apparatus according to claim 4 . The fluid heating device includes:
A solenoid valve between the inlet and the fluid source;
A safety device that cuts off the power to the heater when the temperature in the fluid container exceeds a set value;
The safety device closes the solenoid valve and stops the flow of fluid into the fluid container after shutting off the power supply to the heater when the temperature in the fluid container exceeds a set value. The fluid heating apparatus according to claim 5 . The fluid heating device according to any one of claims 1 to 6, a water supply port for taking in water for heating, a hot water outlet for discharging heated hot water, and water flowing into the fluid heating device A flow meter that measures the flow rate of water and a flow rate adjustment valve that adjusts the flow rate of water flowing into the fluid heating device based on the flow rate of water measured by the flow meter, and the water flow is not detected by the flow meter An electric water heater that cuts off power to the heater of the fluid heating device.

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