Instant electric water heater

Abstract

The object of the present invention is to provide an instantaneous electric water heater that uses a storage tank type heating means in which a heating element is attached around a metal pipe, and that can satisfy the conditions for normal temperature rise without complex control. [Solution] The instantaneous electric water heater 1 according to this disclosure comprises a storage tank 10 for storing liquid, a heating means 30 having a heating element that generates heat when an electric current is passed through it attached to a metal pipe through which the liquid supplied from the storage tank 10 flows, a hot water outlet 50 having a hot water outlet for dispensing the liquid heated by the heating means 30, and a control means 80 for controlling the heating means 30. The control means 80 enters a pause mode in which the operation of the heating means 30 is prohibited for a second predetermined time S0 if the cumulative time of the hot water dispensing operation in which hot water is dispensed from the hot water outlet 50 exceeds a first predetermined time T0.

Description

Technical Field

[0001] The present invention relates to an instant electric water heater, and particularly to a technique for suppressing temperature rises at various locations during operation and continuously operating safely.

Background Art

[0002] An electric water heater of a type that heats water stored in a tank inside a housing like a conventional household electric kettle needs to raise the entire amount of the stored water to a desired temperature and maintain that temperature. Therefore, it may heat an amount of water more than the amount actually used, and moreover, since it is heated for a long time, more energy is required than the actually necessary amount.

[0003] Therefore, an instant electric water heater has been developed that heats only the water supplied by a pump and discharges hot water instead of heating the entire amount of the stored water.

[0004] As a law aimed at ensuring the safety of electrical appliances such as such instant electric water heaters and preventing the occurrence of product hazards and malfunctions, the Electrical Appliances Safety Act has been established. In the Electrical Appliances Safety Act, there is an index called normal temperature rise that defines the upper limit of the temperature of each part of an electrical appliance when a predetermined operation is performed in order to prevent ignition, smoking, burns, etc. from occurring when using the electrical appliance.

[0005] Normal temperature rise is a temperature condition in which a voltage equal to the rated voltage is continuously applied until the temperature rise of each part becomes almost constant, and it is required that the temperature value at a determined measurement location is below a specified value. In order to satisfy the conditions of normal temperature rise, it is desirable to have a structure that effectively dissipates the heat inside the housing so that the temperature rise value at the determined measurement location is below the specified value. For this purpose, for example, increasing the volume of the housing or drilling heat dissipation holes in the housing can be considered, but changing the structure of the housing makes the device itself larger, which is not desirable.

[0006] Furthermore, it is conceivable to install an over-temperature protection device, such as a thermostat, that activates when the temperature rises to a predetermined level, and to activate the thermostat and stop operation before the temperature rises to the predetermined level. However, under the Electrical Appliances and Materials Safety Act, stopping operation with a thermostat is considered to function as an over-temperature protection device that immediately stops the temperature rise in the event of an abnormality, and is not considered to satisfy the normal temperature rise requirement.

[0007] Therefore, it is necessary to satisfy the conditions for normal temperature rise by means other than improving heat dissipation through overheat prevention devices or improvements to the structure of the enclosure. To achieve this, one possible solution is to install temperature sensors in various locations and implement a control system that stops the heater operation each time a temperature sensor detects a predetermined temperature. However, installing temperature sensors in various locations on the product is costly, and the control system becomes complex. In particular, a control system that stops operation every time the temperature reaches the upper limit and restarts operation when it drops to a predetermined temperature would cause hunting, which involves repeatedly stopping and restarting the equipment in a short period of time, and is undesirable. Furthermore, if the heater operation is stopped, it is not possible to heat the water to the desired temperature, and the water heater cannot perform its function.

[0008] Incidentally, some instantaneous electric water heaters use ceramic heaters, as shown in Patent Document 1. A ceramic heater has a heater body that generates heat by Joule heating embedded in a ceramic block, into which a water pipe is placed, and the water flowing through the water pipe in the ceramic block is heated via the heater body (Patent Document 1). Alternatively, there are heaters coated with ceramic placed inside the water pipe. Or, there are heaters such as nichrome wire wrapped around a ceramic water pipe. In an instantaneous electric water heater using a ceramic heater, when water is constantly flowing, the temperature rise of the water pipe itself is low, so the temperature rise inside the product is also low, making it easy to meet the conditions for normal temperature rise. However, in an instantaneous electric water heater using a ceramic heater, if for some reason the heater operates without water flowing through the water pipe, there is a risk that the ceramic, which has a brittle characteristic, will immediately break and malfunction. Therefore, electric water heaters using ceramic heaters tend to malfunction more frequently, or the water flow and heater control to prevent dry boiling and thus prevent malfunctions becomes more complex.

[0009] To avoid the risks associated with using ceramic heaters, electric water heaters have been proposed that employ a heating method in which a heating element that generates heat when electricity is passed through is directly or indirectly attached around a metal pipe, such as a stainless steel pipe. Unlike ceramics, metals such as stainless steel do not immediately break even when heated to high temperatures, thus reducing the risk of malfunction. However, because metals have a higher heat transfer coefficient than ceramics, the temperature rise of the heater is more easily transmitted to other parts, requiring measures to ensure that the conditions for normal temperature rise are met. [Prior art documents] [Patent Documents]

[0010] [Patent Document 1] Japanese Patent Publication No. 2002-186554 [Overview of the Initiative] [Problems that the invention aims to solve]

[0011] This invention has been made in view of the above problems, and aims to provide an instantaneous electric water heater that uses a heating means in which a heating element is attached around a metal tube, and that can satisfy the conditions for normal temperature rise without complex control. [Means for solving the problem]

[0012] The present invention provides the following solutions.

[0013] The instantaneous electric water heater according to the first feature comprises a storage tank for storing liquid, a heating means having a heating element that generates heat when an electric current is passed through it attached around a metal pipe through which the liquid supplied from the storage tank flows, a hot water outlet having a hot water outlet for dispensing the liquid heated by the heating means, and a control means for controlling the heating means. The control means enters a pause mode that prohibits the operation of the heating means for a second predetermined time if the cumulative time of the hot water dispensing operation from the hot water outlet exceeds a first predetermined time.

[0014] According to the invention relating to the first feature, by performing a pause mode that prohibits the operation of the heating means when the cumulative time of hot water supply operation exceeds a first predetermined time, it is possible to prevent the temperature of each part from rising due to the continuation of hot water supply operation. Moreover, unlike control that prohibits the operation of the heating means based on the detected temperature, since the control is performed based on the cumulative time, it does not cause hunting, which is repeated stopping and restarting of the equipment in a short period of time. In particular, in an instantaneous electric water heater that uses a heating means in which a heating element that generates heat by passing electricity around a metal pipe with a high heat transfer coefficient is attached, by performing control based on the cumulative time rather than the detected temperature, the hunting phenomenon can be reliably prevented and the temperature rise can be kept within limits. Furthermore, by continuing the pause mode for a second predetermined time, the temperature of each part that has risen can be lowered over time, and when hot water supply operation is performed again, it is possible to restart operation from a lower temperature state.

[0015] Furthermore, the instantaneous electric water heater relating to the second feature is the same as the instantaneous electric water heater relating to the first feature, and the control means performs control to terminate the pause mode when the duration of the pause mode exceeds a second predetermined time, and to reset the cumulative time of the hot water supply operation.

[0016] According to the invention relating to the second feature, the control means terminates the pause mode when the duration of the pause mode has elapsed to a second predetermined time, and resets the cumulative time of the hot water supply operation, thereby allowing the temperature of each part to be sufficiently reduced before the next hot water supply operation can be resumed under the same conditions.

[0017] Furthermore, the instantaneous electric water heater relating to the third feature is the same as the instantaneous electric water heater relating to the first feature, and the control means performs control to reset the cumulative time of the hot water supply operation when the time interval between one hot water supply operation and the next hot water supply operation exceeds a third predetermined time.

[0018] According to the invention relating to the third feature, the control means performs control to reset the cumulative time of the hot water dispensing operation when the time interval between one hot water dispensing operation and the next hot water dispensing operation exceeds a third predetermined time, thereby preventing the idle mode from being unnecessarily activated even though the temperature of each part has sufficiently decreased.

[0019] Furthermore, the instantaneous electric water heater relating to the fourth feature is an instantaneous electric water heater relating to the first feature, wherein if the continuous hot water supply time of the hot water supply operation does not exceed the fourth predetermined time, the pause mode is activated when the cumulative time of the hot water supply operation exceeds the first predetermined time, and if the continuous hot water supply time of the hot water supply operation exceeds the fourth predetermined time, the pause mode is activated when the cumulative time exceeds the fifth predetermined time, which is shorter than the first predetermined time.

[0020] According to the invention related to the fourth feature, when the continuous hot water discharge time of the hot water discharge operation does not exceed the fourth predetermined time, the standby mode is entered when the cumulative time of the hot water discharge operation exceeds the first predetermined time. When the continuous hot water discharge time of the hot water discharge operation exceeds the fourth predetermined time, the standby mode is entered when exceeding the fifth predetermined time shorter than the first predetermined time. By doing so, it is possible to surely suppress the occurrence of temperature rise in each part and continue stable operation.

Effect of the Invention

[0021] According to the present invention, in an instantaneous electric water heater using a heating means in which a heating element is attached around a metal pipe, it is possible to provide an instantaneous electric water heater that can satisfy the conditions of normal temperature rise without performing complicated control.

Brief Description of the Drawings

[0022] [Figure 1] FIG. 1 is a perspective view showing the overall structure of the instantaneous electric water heater 1 according to the present embodiment. FIG. 1(a) shows a perspective view seen from above, and FIG. 1(b) shows a perspective view seen from below. [Figure 2] FIG. 2 is a side view of the instantaneous electric water heater 1 according to the present embodiment. [Figure 3] FIG. 3 is a schematic diagram showing the internal structure of the instantaneous electric water heater 1 according to the present embodiment. [Figure 4] FIG. 4 is a block diagram for explaining the hardware configuration and software functions in the instantaneous electric water heater 1 according to the present embodiment. [Figure 5] FIG. 5 is a flowchart showing the hot water discharge operation of the instantaneous electric water heater 1 according to the present embodiment. [Figure 6] FIG. 6 is a flowchart showing the standby mode of the instantaneous electric water heater 1 according to the present embodiment.

Mode for Carrying Out the Invention

[0023] The following describes embodiments for carrying out the present invention with reference to the figures. However, this is merely an example, and the technical scope of the present invention is not limited thereto.

[0024] [Overall configuration of Instant Electric Water Heater 1] The overall configuration of the instantaneous electric water heater 1 according to this embodiment will be explained using Figures 1 to 3. The instantaneous electric water heater 1 in the present invention is an instantaneous electric water heater 1 that heats water supplied from a storage tank and dispenses hot water.

[0025] Figure 1 is a perspective view showing the overall structure of the instantaneous electric water heater 1 according to this embodiment, where Figure 1(a) is a perspective view from above and Figure 1(b) is a perspective view from below. Figure 2 is a side view of the instantaneous electric water heater 1 according to this embodiment. Figure 3 is a schematic diagram showing the internal structure of the instantaneous electric water heater 1 according to this embodiment. Figure 4 is a block diagram for explaining the hardware configuration and software functions of the control means 80 of the instantaneous electric water heater 1 according to this embodiment.

[0026] As shown in Figures 1 to 3, the instantaneous electric water heater 1 according to this embodiment heats the liquid stored in the water heater body and discharges it outside the water heater body. It comprises a storage tank 10 for storing the liquid to be heated, a supply means 20 for dispensing the liquid, a heating means 30 for heating the liquid, a pouring pipe 40, a dispensing means 50 for dispensing the heated liquid, a power supply means 60 for supplying power to the heating means 30 and the control means, a housing 70, and a control means 80. Note that the storage tank 10 is not shown in Figure 3.

[0027] The storage tank 10 in this embodiment is a container having a predetermined capacity, and is equipped with an inlet (not shown) at the top into which liquid can be supplied by the user, and an outlet (not shown) at the bottom for the liquid to flow out. The inlet may be provided with an openable and closable lid or cap. The storage tank 10 itself may be detachable from the housing 70, or it may be fixed to the housing 70. The storage tank 10 may be installed inside the housing 70, or it may be installed outside the housing 70, as shown in Figures 1 to 3.

[0028] The supply means 20 pumps the liquid held by the storage tank 10 towards the heating means 30 and the hot water dispensing means 50, and in this embodiment, an electric pump is used.

[0029] The heating means 30 heats the liquid pumped from the storage tank 10 by the supply means 20 to a desired temperature. In the present invention, the heating means 30 is formed by directly or indirectly attaching a heating element that generates heat when an electric current is passed through it to the periphery of a metal pipe such as a stainless steel pipe.

[0030] The hot water supply pipe 40 is a path that guides the heated and pressurized hot water to the hot water dispensing means 50.

[0031] The hot water dispensing means 50 is connected to the pouring pipe 40 and dispenses hot water supplied through the pouring pipe 40. It comprises a nose portion 51 that protrudes horizontally from the housing 70 and a hot water outlet 52 formed vertically downward on the lower surface of the nose portion 51.

[0032] The power supply means 60 is connected to a household power supply or general power supply and supplies power for operation to the supply means 20, heating means 30, etc., and includes a power plug and power cord (not shown).

[0033] The housing 70 houses the storage tank 10, supply means 20, heating means 30, hot water dispensing means 50, control means 80, etc., either internally or externally, and in this embodiment, it is formed in a cylindrical shape. An operation panel (not shown) is formed on the surface of the housing 70. The storage tank 10, hot water dispensing means 50, and housing 70 form the main body of the water heater.

[0034] An operation panel (not shown) formed on one side of the housing 70 includes a power button, a temperature control button, a mode selection button, a hot water dispensing button, and a water supply / child lock button. The operation panel also includes a setting display section that shows the current temperature, set temperature, operating status, etc.

[0035] The control means 80 includes means for outputting control signals to the supply means 20 and the heating means 30, and timing means for measuring time, and outputs control signals to the supply means 20 and the heating means 30 based on the detection result of the timing means.

[0036] Using the block diagram shown in Figure 4, the hardware configuration and software functions of the control means 80 provided in the instantaneous electric water heater 1 according to this embodiment will be explained.

[0037] The control means 80 includes a CPU (Central Processing Unit), RAM (Random Access Memory), ROM (Read Only Memory), etc., and reads a predetermined program to realize the functions of the timing module 81, storage module 82, temperature detection module 83, signal generation module 84, calculation module 85, and comparison module 86.

[0038] The timing module 81 is a module for measuring the time during which the supply means 20 and heating means 30 are operating and the time during which they are idle.

[0039] The memory module 82 is a module for storing information using semiconductor memory or the like, and in particular includes a setting data storage unit 82a for storing pre-set data and a timing data storage unit 82b for storing the time measured by the timing module 81.

[0040] The temperature detection module 83 is a module that includes temperature sensors installed at various locations in the instantaneous electric water heater 1 and detects the temperature at each location.

[0041] The signal generation module 84 is a module that generates signals for operation start commands, operation stop commands, or operation prohibition commands to be transmitted to the supply means 20 and the heating means 30.

[0042] The calculation module 85 is a module that performs arithmetic operations, differential and integral calculus, etc., on information acquired by the timing module 81 and the temperature detection module 83, as well as information stored in the memory module 82.

[0043] The comparison module 86 is a module that compares information stored in the memory module 82 and information obtained through calculations performed by the calculation module 85 to determine whether they are greater or lesser.

[0044] The electric water heater 1, as described above, stores liquid in the storage tank 10, and when an operating part (not shown) is operated, a signal from the control means 80 activates the supply means 20 to pump out the liquid, the heating means 30 heats the liquid to the desired temperature, and a stream of hot water is dispensed from the outlet 52 of the hot water dispensing means 50 via the pouring pipe 40.

[0045] [Instantaneous electric water heater 1 hot water supply operation] Next, the hot water supply operation of the instantaneous electric water heater 1 according to this embodiment will be explained using Figure 5. Figure 5 is a flowchart showing the hot water supply operation of the instantaneous electric water heater 1 according to this embodiment.

[0046] <Steps S100-S110: Start of hot water supply operation> When a user supplies water to the storage tank 10 and then presses the hot water dispensing button on the control panel, the hot water dispensing operation begins. When the hot water dispensing operation begins, the control means 80 operates the timing module 81 to reset the time interval r from the previous hot water dispensing operation (step S100), then operates the signal generation module 84 to generate operation signals to the supply means 20 and the heating means 30, and operates the supply means 20 and the heating means 30 to perform the hot water dispensing operation. The control means 80 also operates the timing module 81 to time the hot water dispensing operation time t (step S110). At this time, the hot water dispensing operation is performed for a predetermined hot water dispensing operation time t, which may be the time from when the user presses the operation button until they release it, or it may be a time that has been set in advance and stored in the setting data storage unit 82a of the storage module 82. The hot water dispensing operation time t, which is the length of time during which the hot water dispensing operation is performed, is measured by the timing module 81 and stored in the timing data storage unit 82b of the storage module 82.

[0047] <Step S120: Determination of cumulative hot water dispensing time> Once the hot water supply operation starts, the next step is to determine whether the cumulative hot water supply time, which is the cumulative time of the hot water supply operation up to that point, has exceeded the first predetermined time T0 (step S120).

[0048] In step S120, the memory module 82 and the calculation module 85 are used to calculate a new cumulative hot water dispensing time, which is the sum of the cumulative hot water dispensing time stored in the timing data storage unit 82b of the memory module 82 and the current hot water dispensing time t measured by the timing module 81. Then, the comparison module 86 compares the predetermined time T0 stored in the setting data storage unit 82a with the new cumulative hot water dispensing time to make a determination. If it is determined in step S120 that the new cumulative hot water dispensing time does not exceed the predetermined time T0 (N in S120), the process proceeds to step S130. If it is determined that the new cumulative hot water dispensing time exceeds the predetermined time T0 (Y in S120), the process proceeds to the second predetermined time S0 pause mode shown in Figure 6. The pause mode will be described later.

[0049] <Step S130: Determination of the end of hot water supply> In step S120, if it is determined that the cumulative hot water dispensing time does not exceed a predetermined time T0, the control means 80 then determines whether the hot water dispensing operation has ended (step S130). The end of the hot water dispensing operation is determined by detecting that the user has released their finger from the hot water dispensing button, or by determining whether the hot water dispensing operation time measured by the timing module 81 has reached a predetermined hot water dispensing operation time stored in the pre-set data storage unit 82a. In step S130, if it is determined that the hot water dispensing operation has ended, the hot water dispensing operation time measured by the timing module 81 is stored in the timing data storage unit 82b, and the process proceeds to step S140 (Y in S130). At this time, the timing data storage unit 82b adds the hot water dispensing operation time measured this time to the cumulative hot water dispensing time accumulated so far and stores it as a new cumulative hot water dispensing time. If it is determined in step S130 that the hot water supply has not finished (N in S130), the process returns to step S110, and the determinations in steps S120 and S130 are repeated while continuing to measure the hot water supply operation time.

[0050] <Step S140: Determination of cumulative hot water dispensing time> In step S130, if it is determined that the hot water dispensing operation has ended, the next step is to determine whether the cumulative hot water dispensing time, which is the cumulative time of the hot water dispensing operation up to that point, has exceeded the first predetermined time T0 (step S140). The determination of the cumulative hot water dispensing time in step S140 is the same operation as the determination of the cumulative hot water dispensing time in step S120, so the explanation is omitted here. In step S140, if it is determined that the cumulative hot water dispensing time has exceeded the predetermined time T0 (N in S140), the process proceeds to step S150. If it is determined that the cumulative hot water dispensing time has exceeded the predetermined time T0 (Y in S140), the process proceeds to the second predetermined time S0 pause mode shown in Figure 6. The pause mode will be described later.

[0051] <Step S150: Measuring time intervals> In step S120, if it is determined that the cumulative hot water dispensing time does not exceed a predetermined time T0, the control means 80 then operates the timing module 81 to measure the time interval r of the hot water dispensing operation (step S150). That is, as determined in step S130, the hot water dispensing operation has already ended, so the time interval until the next hot water dispensing operation is measured.

[0052] <Step S160: Determining whether or not hot water will be dispensed next> Next, the control means 80 determines whether or not there is a next hot water supply (step S160). The determination of whether or not there is a hot water supply is made by detecting the presence or absence of hot water supply, such as when the user presses the hot water supply button on the operation panel. If no next hot water supply is detected in step S160 (N in step S160), the process proceeds to step S170. If the next hot water supply is detected in step S160 (Y in step S160), the process returns to step S100, the time interval r that was being measured is reset, and the hot water supply operation time t in step S110 is measured.

[0053] <Step S170: Determining the time interval> In step S160, if no further hot water is detected, the next step is to determine whether the time interval has exceeded a third predetermined time R0 (step S170).

[0054] In step S170, a determination is made by comparing a predetermined time R0 stored in the setting data storage unit 82a with the time interval r measured by the timing module 81, using the storage module 82 and the comparison module 86. If it is not determined in step S170 that the time interval r has exceeded the predetermined time R0 (N in step S170), the process returns to step S150, and the timing of the time interval r continues, while the determinations in steps S160 and S170 are repeated. If it is determined in step S170 that the time interval r has exceeded the predetermined time R0 (Y in step S170), the process proceeds to step S180.

[0055] <Step S180: Reset cumulative hot water dispensing time> In step S170, if it is determined that the time interval r has exceeded a predetermined time R0, the control means 80 resets the cumulative hot water dispensing time t stored in the timing data storage unit 82b of the memory module 82 to zero and terminates the hot water dispensing operation (step S180). The control in steps S170 and S180 means that if there is no further hot water dispensing operation for a predetermined time R0, such as 5 minutes, it is determined that the internal temperature has dropped sufficiently, the cumulative hot water dispensing time is reset, the series of hot water dispensing operations is terminated, and the system returns to its initial state. In this way, it is possible to prevent the pause mode from being unnecessarily activated even though the temperature of each part has dropped sufficiently.

[0056] [Sleep mode for instant electric water heater 1] Next, the pause mode of the instantaneous electric water heater 1 according to this embodiment will be explained using Figure 6. Figure 6 is a flowchart showing the pause mode of the instantaneous electric water heater 1 according to this embodiment.

[0057] <Step S200: Start of pause mode and start of timing> In step S120 or step S140 shown in the flowchart of Figure 5, if the cumulative hot water supply time exceeds a predetermined time T0, the control means 80 activates the signal generation module 84 to generate an operation prohibition signal to the supply means 20 and the heating means 30, and starts the pause mode, and also activates the timing module 81 to start timing the pause mode duration s (step S200).

[0058] When the pause mode is activated, even if the supply means 20 and heating means 30 are operating, they will immediately stop operating based on the operation prohibition signal generated by the signal generation module 84, and operation will be prohibited for a predetermined period of time thereafter. While the pause mode is in effect, even if the user presses the hot water button, the operation command will be canceled due to the operation prohibition signal, and the equipment will not operate.

[0059] <Step S210: Determination of the duration s of the pause mode> When the timing of the pause mode duration is started in step 200, the control means 80 then uses the memory module 82 and the comparison module 86 to determine whether the pause mode duration s has exceeded a third predetermined time S0 (step S210).

[0060] In step S210, the comparison module 86 compares the duration of the pause mode stored in the timing data storage unit 82b of the memory module 82 with a predetermined time S0 that is pre-stored in the setting data storage unit 82a. If the duration of the pause mode s does not exceed the predetermined time S0, the determination in step S210 is repeated at predetermined intervals. If the duration of the pause mode s exceeds the predetermined time S0, the process proceeds to step S220.

[0061] <Step S220: Ending sleep mode> In step S210, if the duration of the pause mode s exceeds a predetermined time S0, the signal generation module 84 generates an operation-enabled signal to the supply means 20 and the heating means 30, the operation prohibition signal is released, and the pause mode ends (step S220).

[0062] At this time, the cumulative hot water dispensing time t stored in the timing data storage unit 82b is reset, and the cumulative hot water dispensing time is set to 0, after which the series of hot water dispensing operations and pause modes are terminated.

[0063] <Example 1> As Example 1, we will describe an example in which the short-time hot water supply mode operation is repeated. The short-time hot water supply mode operation is an operation in which the hot water supply time t is within the fourth predetermined time of 120 seconds, for example, t = 20 seconds. Furthermore, the time interval r between preceding and succeeding short-time hot water supply mode operations is assumed to be within R0 = 300 seconds.

[0064] In short-time hot water dispensing mode, the pause mode is initiated when the cumulative hot water dispensing time, which is the cumulative value of the hot water dispensing time, exceeds a predetermined cumulative time T0 = 1200 seconds. When the pause mode is initiated, the signal generation module 84 generates an operation prohibition signal, and this signal is transmitted to each device, such as the supply means 20 and the heating means 30. During pause mode, even if the user presses the hot water dispensing button, the operation command is canceled due to the operation prohibition signal, and the device does not operate. In addition, the display on the operation panel of the housing 70 shows a visual indication that the device is in pause mode. The duration of pause mode is S0 = 300 seconds. After 300 seconds of pause mode, an operation-ready signal is generated, the operation prohibition signal is released, and the device returns to a state where normal hot water dispensing mode operation is possible. At this time, the cumulative hot water dispensing time is reset to zero, so if the same short-time hot water dispensing mode operation is repeated, the 1200-second hot water dispensing operation can be performed again.

[0065] <Example 2> As Example 2, we will describe an example of repeatedly operating in long-duration hot water supply mode. Long-duration hot water supply mode operation is, for example, an operation in which the hot water supply time for one cycle exceeds the fourth predetermined time of 120 seconds, specifically 121 seconds or more, and is performed continuously. Furthermore, the time interval r between preceding and succeeding long-duration hot water supply mode operations is assumed to be R0 = 300 seconds or less.

[0066] When the cumulative hot water supply time accumulates through repeated long-duration hot water supply operation, it is desirable that the pause mode be activated when a fifth predetermined time, shorter than the first predetermined time at which the pause mode is activated by repeatedly short-duration hot water supply operation, elapses, for example, when the cumulative hot water supply time reaches T0 = 600 seconds. When the predetermined cumulative time T0 = 600 seconds has elapsed due to long-duration hot water supply operation, the pause mode is activated. When the pause mode is activated, the signal generation module 84 generates an operation prohibition signal, and this operation prohibition signal is transmitted to each device, such as the supply means 20 and the heating means 30. During the pause mode, even if the user presses the hot water supply button, the operation command is canceled due to the operation prohibition signal, and the device does not operate. In addition, the display section of the operation panel of the housing 70 shows a display that allows the user to visually confirm that the device is in pause mode. The duration of the pause mode is S0 = 300 seconds. After 300 seconds of pause mode, an operation-ready signal is generated, the operation prohibition signal is released, and the device returns to a state where normal hot water supply mode operation is possible. At this time, the cumulative hot water dispensing time is reset to zero, so if the same long-duration hot water dispensing mode operation is repeated, the 600-second hot water dispensing operation can be performed again.

[0067] <Example 3> As Example 3, we will describe an example in which the short-time hot water supply mode operation described in Example 1 and the long-time hot water supply mode operation described in Example 2 are combined. The time interval r between the preceding and succeeding hot water supply mode operations is assumed to be R0 = 300 seconds or less.

[0068] When short-time and long-time hot water supply modes are combined, it is desirable that the pause mode be activated after a short cumulative hot water supply time, for example, when T0 = 600 seconds, has elapsed, similar to when long-time hot water supply mode is repeated. This is to suppress the premature temperature rise of various parts caused by long-time hot water supply mode operation.

[0069] In this way, by adjusting the cumulative hot water dispensing time required to activate the pause mode according to the length of a single hot water dispensing operation, it is possible to maintain stable operation while reliably suppressing temperature increases in each part.

[0070] According to the operating mode of the present invention, the control means 80 performs a pause mode in which the operation of the heating means 30 is prohibited when the cumulative time of the hot water dispensing mode operation exceeds a first predetermined time T0, thereby preventing the temperature of each part from rising due to the continuation of the hot water dispensing mode operation. Moreover, unlike control that prohibits hot water dispensing based on the detected temperature, since the control is performed based on the cumulative time, it does not cause hunting, which is repeated stopping and restarting of the equipment in a short period of time. In particular, in an instantaneous electric water heater 1 using a heating means 30 made of a stainless steel heater with a high heat transfer coefficient, by performing control based on the cumulative time rather than the detected temperature, the hunting phenomenon can be reliably prevented and the temperature rise can be kept within limits. Furthermore, by continuing the pause mode for a second predetermined time S0, the temperature of each part that has risen can be lowered over time, and when the next hot water dispensing mode operation is performed, it is possible to restart the operation from a state where the temperature has decreased.

[0071] Furthermore, the control means 80 terminates the pause mode when the duration of the pause mode has elapsed to a second predetermined time S0, and resets the cumulative time of the hot water dispensing mode operation, thereby allowing the temperature to drop sufficiently before restarting the next hot water dispensing mode operation under the same conditions.

[0072] Furthermore, the control means 80 can prevent the idle mode from being unnecessarily activated even though the temperature of each part has sufficiently decreased by performing control to reset the cumulative hot water dispensing time of the hot water dispensing operation when the time interval between one hot water dispensing operation and the next hot water dispensing operation exceeds a third predetermined time R0.

[0073] Furthermore, the control means 80 can maintain stable operation while reliably suppressing premature temperature increases in various parts due to long-duration hot water supply operation by entering a pause mode when the continuous hot water supply time exceeds a fourth predetermined time, or when it exceeds a fifth predetermined time which is shorter than the first predetermined time.

[0074] Although embodiments of the present invention have been described above, the present invention is not limited to these embodiments. Furthermore, the effects described in the embodiments of the present invention are merely a list of the most preferred effects arising from the present invention, and the effects of the present invention are not limited to those described in the embodiments.

[0075] Furthermore, the embodiments described above are explained in detail for the purpose of clearly illustrating the present invention, and are not necessarily limited to those comprising all the configurations described. [Industrial applicability]

[0076] This invention's instantaneous electric water heater can be applied to instantaneous electric water heaters of various sizes, whether for general household or commercial use. [Explanation of Symbols]

[0077] 1. Instant electric water heater 10 Storage tanks 20 Means of supply 30 Heating means 40 Pouring pipe 50 Hot water supply method 51 Nose section 52 Hot water outlet 60 Power supply means 70 cabinets 80 Control means 81 Timing Module 82 memory modules 82a Setting data storage unit 82b Timing data storage unit 83 Temperature detection module 84 Signal Generation Module 85 Arithmetic Modules 86 Comparison Module

Claims

1. An instantaneous electric water heater comprising: a storage tank for storing liquid; a heating means having a heating element that generates heat when an electric current is passed through a metal pipe through which the liquid supplied from the storage tank flows; a hot water outlet having a hot water outlet for dispensing the liquid heated by the heating means; and a control means for controlling the heating means, The control means enters a pause mode that prohibits the operation of the heating means for a second predetermined period of time if the cumulative time of the hot water dispensing operation from the hot water dispensing means exceeds a first predetermined period of time. Instant electric water heater.

2. The control means terminates the pause mode when the duration of the pause mode exceeds a second predetermined time, and also performs control to reset the cumulative time of the hot water supply operation. The instantaneous electric water heater according to claim 1.

3. The control means performs a control to reset the accumulated time of the hot water dispensing operation if the time interval between the hot water dispensing operation and the next hot water dispensing operation exceeds a third predetermined time. The instantaneous electric water heater according to claim 1.

4. The control means, if the continuous hot water supply time of the hot water supply operation does not exceed the fourth predetermined time, performs the pause mode when the cumulative time of the hot water supply operation exceeds the first predetermined time, and if the continuous hot water supply time of the hot water supply operation exceeds the fourth predetermined time, performs the pause mode when it exceeds a fifth predetermined time which is shorter than the first predetermined time. The instantaneous electric water heater according to claim 1.

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