JP3502615B2 - Electric pot with flow sensor - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric pot with a flow rate sensor equipped with a flow rate sensor for measuring the discharge amount of hot and cold water, and more specifically, it is caused by the contamination of a transparent tube constituting the flow rate sensor over time. The present invention relates to an improvement for avoiding a decrease in the sensitivity of a flow rate sensor and the accompanying erroneous measurement.

[0002]

2. Description of the Related Art An electric kettle for boiling and keeping hot water for drinking, cooking, etc. by an electric heater is widely used in general households. In recent years, an electric pot is generally equipped with a control section using a microprocessor, a temperature sensor, etc., and an operation panel including a push button switch and a liquid crystal display. For example, the control unit heats the electric heater until the hot water temperature set on the operation panel is reached based on the detection signal of the temperature sensor, and then executes automatic control to switch to the heater for heat retention.

[0003] Further, a mainstream is one that has an electric pump built therein and electrically supplies hot water. The user can supply hot water from the electric pot to a predetermined container simply by pressing the hot water supply instruction button on the operation panel. In this case, hot water is normally discharged from the discharge port (hot water spout) only while the hot water supply instruction button is being pressed, and the discharge of hot water is stopped when the finger is released from the hot water supply instruction button. The control unit using the microprocessor also executes the processing for controlling the electric pump according to the operation of the operation panel.

In recent years, an attempt has been made to add a fixed amount hot water supply function to an electric pot provided with a control section using a microprocessor and an electric pump as described above (see, for example, Japanese Patent Laid-Open No. 10-328028). . That is, the hot water is discharged from the electric pot by the electric pump until the hot water supply amount set on the operation panel is reached, and the electric pump is automatically stopped when the hot water supply amount reaches the set hot water supply amount. With this function, an appropriate amount of hot water can be obtained from the electric pot without using a measuring cup or the like.

The present applicant has previously filed a patent application relating to the invention of an electric pot that realizes the above-described fixed-quantity hot water supply function by using a flow rate sensor having a unique structure (Japanese Patent Application 2).
001-041064). This flow rate sensor is provided with a rotary member having a spiral-shaped rotary blade that rotates around an axis along the flow direction of water in a transparent tube inserted in the middle of the discharge tube, and is arranged outside the transparent tube. A light emitting element and a light receiving element for irradiating light to the rotary blade in the transparent tube from a direction substantially perpendicular to the axis are provided.

When water flows in the transparent tube, the rotary member rotates, and the light emitted from the light emitting element passes through the gap of the rotary blade to reach the light receiving element, and the light emitted from the light emitting element rotates the rotary blade. By alternately repeating the light blocking state in which the light is blocked and the light does not reach the light receiving element, a substantially sinusoidal electric signal is obtained from the light receiving element. By comparing this electric signal with a predetermined threshold value, a rectangular wave in which the transmission potential corresponding to the transmission state and the light shielding potential corresponding to the light shielding state are alternately repeated is generated, and the period or frequency of this rectangular wave is determined. Based on this, the flow rate or discharge amount of hot and cold water per unit time can be obtained.

[0007]

However, from the results of the life test and other test results thereafter, when the electric pot is used for a long time, the inner wall of the transparent tube of the flow sensor becomes dirty due to the deposition of minerals (calcium carbonate, etc.), as a result,
It was found that the error in the measured value of the flow rate or discharge amount of water per unit time was large. That is, the transparency of the transparent tube is reduced due to the contamination of the inner wall, and the ratio of the light emitted from the light emitting element reaching the light receiving element through the gap of the rotating blades in the transparent tube is reduced. The level on the transmission potential side of the substantially sinusoidal electric signal approaches the intermediate level.

For example, in the initial stage of use, a substantially sinusoidal electric signal output from the light receiving element is a substantially sinusoidal voltage varying from 0 V to 5 V, where 0 V is the level on the transmission potential side and 5 V is the light shielding potential. At the side level, as the transparency of the transparent tube decreases, the valley of the substantially sinusoidal voltage rises from 0 volt and approaches an intermediate level (2.5 volt). As a result, when the threshold value is set to an intermediate level, the rectangular wave generated by comparison with the threshold value may not reflect the rotation speed of the rotating member correctly, resulting in a large measurement value error. Become.

The dirt on the inner wall of the transparent tube as described above is
It can be cleaned by maintenance called citric acid cleaning. If the transparency of the transparent tube becomes higher (restored) by the citric acid cleaning, the error in the measurement value of the flow sensor becomes smaller again. However, the citric acid cleaning is originally carried out when the inner wall of the tank becomes extremely dirty, and at that time, the inner wall of the transparent tube of the flow sensor may already be contaminated.

Further, the accumulated use time (or the number of times of boiling water) of the electric pot is stored in a non-volatile memory, and when a certain time (number of times) has elapsed, the execution of citric acid cleaning is displayed and the user is informed by a buzzer sounding. It is possible to do it. However, also in this case, it is difficult to uniformly determine the relationship between the cumulative usage time (or the number of times of boiling water) and the stain on the inner wall of the transparent tube of the flow rate sensor. This is because the degree of progress of dirt on the inner wall of the transparent tube largely depends on the amount of minerals contained in the water used and the conditions such as the usage form.

The present invention solves the above-mentioned conventional problems, and avoids a decrease in the sensitivity of the flow sensor due to the time-dependent contamination of the transparent tube constituting the flow sensor and the accompanying erroneous measurement. An object is to provide an electric pot with a sensor. It is also an object of the present invention to notify an appropriate time when the citric acid cleaning should be carried out in order to eliminate the stain on the inner wall of the transparent tube of the flow rate sensor.

[0012]

[0013]

[0014]

A first structure of an electric pot according to the present invention comprises a heater and a tank for heating water, an electric pump and a discharge pipe for discharging hot water in the tank to the outside. A flow rate sensor inserted in the middle of the discharge pipe and a control unit for measuring the discharge amount of the hot water based on the output signal of the flow rate sensor. The flow rate sensor is arranged in the transparent tube along the flowing direction of the hot water. A rotary member having a spiral-shaped rotary blade that rotates around an axis, and a light emitting element and a light receiving element that are arranged outside the transparent tube and emit light from a direction substantially perpendicular to the axis toward the rotary blade inside the transparent tube. When the rotating member rotates, the light emitted from the light emitting element passes through the gap of the rotary blade and reaches the light receiving element, and the light emitted from the light emitting element is blocked by the rotary blade to receive the light receiving element. Reached The light-receiving element is configured to obtain a substantially sinusoidal electric signal by alternately repeating the light-shielding state and the control section outputs the substantially sinusoidal electric signal output from the light-receiving element of the flow sensor. By comparing with the threshold value, a rectangular wave in which the transmission potential corresponding to the transmission state and the light shielding potential corresponding to the light blocking state are alternately repeated is generated, and the discharge amount of hot and cold water is obtained from the cycle or frequency of the rectangular wave. In the initial stage of use of the electric pot, the electric signal having a substantially sinusoidal waveform is set such that the level on the transmission potential side is saturated and the period on the transmission potential side from the intermediate level is longer than the period on the light shielding potential side. It is characterized by being

For example, by adjusting the resistance values of the current limiting resistor of the light emitting element of the flow sensor and the sensitivity adjusting resistor of the light receiving element, the substantially sinusoidal electric signal output from the light receiving element is set as described above. can do.

According to this structure, when the electric pot is used for a long period of time, the transparency of the transparent tube of the flow sensor is lowered due to dirt on the inner wall of the transparent tube of the flow sensor, and a substantially sinusoidal waveform output from the light receiving element of the flow sensor is obtained. Since it is possible to delay the time when the transmission potential side level of the electric signal approaches the intermediate level, the life of the flow sensor can be extended.

A second configuration of the electric pot according to the present invention is a heater and a tank for heating water, an electric pump and a discharge pipe for discharging hot water in the tank to the outside, and a middle of the discharge pipe. A flow rate sensor inserted into the transparent tube, and a control unit that measures the discharge rate of the hot water based on the output signal of the flow rate sensor. The flow rate sensor rotates around the axis along the flowing direction of the hot water in the transparent tube. A rotating member having a spiral-shaped rotating blade; and a light-emitting element and a light-receiving element that are arranged outside the transparent tube and emit light from a direction substantially perpendicular to the axis toward the rotating blade in the transparent tube. According to the rotation, the light emitted from the light emitting element passes through the gap of the rotary blade and reaches the light receiving element, and the light shielding state in which the light emitted from the light emitting element is blocked by the rotary blade and does not reach the light receiving element. But By being alternately repeated, the light receiving element is configured to obtain a substantially sinusoidal electric signal, and the control unit compares the substantially sinusoidal electric signal output from the light receiving element of the flow rate sensor with a threshold value. As a result, a rectangular wave in which a transmission potential corresponding to the transmission state and a light shielding potential corresponding to the light shielding state are alternately repeated is generated,
The discharge amount of hot and cold water is obtained from the period or frequency of the rectangular wave, and the threshold value is closer to the light-shielding potential side than the intermediate level of the change range of the substantially sine wave electric signal output from the light receiving element. In addition to the first threshold value set to the level closer to the light-shielding potential side than the intermediate level of the change range of the substantially sine-wave electric signal output from the light receiving element, the first threshold value The second threshold value is set closer to the level on the transmission potential side than that, and the control unit generates the first rectangular wave generated using the first threshold value and the second rectangular wave using the second threshold value. It is characterized in that the cycle or frequency is compared with the generated second rectangular wave, and if the difference between the cycle or frequency of the first rectangular wave and the second rectangular wave becomes larger than a predetermined value, a predetermined notification is performed.

According to the above construction, the transparency of the transparent tube is lowered by the contamination of the inner wall of the transparent tube of the flow sensor, and the level of the transmission potential of the substantially sinusoidal electric signal output from the light receiving element of the flow sensor is the intermediate level. As the first rectangular wave generated using the first threshold value is approached by the second rectangular wave generated using the second threshold value before being affected by the dirt on the inner wall of the transparent tube. Under the influence, an error will occur in the cycle or frequency. Therefore,
A predetermined notification is given before the error of the discharge amount of hot and cold water obtained from the cycle or frequency of the first rectangular wave becomes large, and the user is urged to carry out citric acid cleaning for the purpose of eliminating stains on the inner wall of the transparent tube. You can

A third configuration of the electric pot according to the present invention is a heater and a tank for heating water, an electric pump and a discharge pipe for discharging hot and cold water in the tank to the outside, and a middle of the discharge pipe. A flow rate sensor inserted into the transparent tube, and a control unit that measures the discharge rate of the hot water based on the output signal of the flow rate sensor. The flow rate sensor rotates around the axis along the flowing direction of the hot water in the transparent tube. A rotating member having a spiral-shaped rotating blade; and a light-emitting element and a light-receiving element that are arranged outside the transparent tube and emit light from a direction substantially perpendicular to the axis toward the rotating blade in the transparent tube. According to the rotation, the light emitted from the light emitting element passes through the gap of the rotary blade and reaches the light receiving element, and the light shielding state in which the light emitted from the light emitting element is blocked by the rotary blade and does not reach the light receiving element. But By being alternately repeated, the light receiving element is configured to obtain a substantially sinusoidal electric signal, and the control unit compares the substantially sinusoidal electric signal output from the light receiving element of the flow rate sensor with a threshold value. As a result, a rectangular wave in which a transmission potential corresponding to the transmission state and a light shielding potential corresponding to the light shielding state are alternately repeated is generated,
The discharge amount of hot and cold water is obtained from the period or frequency of the rectangular wave, and the threshold value is closer to the light-shielding potential side than the intermediate level of the change range of the substantially sine wave electric signal output from the light receiving element. In addition to the first threshold value set to the level closer to the light-shielding potential side than the intermediate level of the change range of the substantially sine-wave electric signal output from the light receiving element, the first threshold value The second threshold value is set closer to the level on the transmission potential side than that, and the control unit generates the first rectangular wave generated using the first threshold value and the second rectangular wave using the second threshold value. Compare the pulse width with the generated second rectangular wave,
When the difference between the pulse widths of the rectangular wave and the second rectangular wave becomes larger than a predetermined value, a predetermined notification is given.
According to this configuration, the second rectangular wave is affected by the influence of the dirt on the inner wall of the transparent tube before the first rectangular wave is affected, and an error occurs in the pulse width. Therefore, similar to the above configuration, a predetermined notification is given before the error in the discharge amount of hot and cold water obtained from the cycle or frequency of the first rectangular wave becomes large, and citric acid cleaning for the purpose of eliminating dirt on the inner wall of the transparent tube. The user can be urged to carry out.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view of an electric pot according to an embodiment of the present invention. The electric pot 1 is provided with a tank 12 made of double stainless steel with a vacuum layer sandwiched inside a substantially cylindrical pot body 11. By having the same structure as a so-called thermos, it is configured so that a predetermined hot water temperature can be maintained for a certain period of time without energizing the electric heater.

An electric heater 13 for boiling water and keeping warm is attached to a recess formed in the bottom of the tank 12. An opening 14 for hot water supply (discharging) is provided at the bottom of the tank 12, and the opening 14 communicates with the input side of the electric pump 15 by an input conduit 15a. Electric pump 1
The conduit 15b on the output side of 5 is connected to the base end side of the discharge pipe 16 that extends substantially vertically from the bottom of the electric pot 1 to the upper part thereof. The tip end side of the discharge pipe 16 reaches the discharge port 19 through the flow rate sensor 17 and the leak prevention valve mechanism 18 at the time of falling. The discharge pipe 16 is made of a transparent glass pipe, and the water surface therein can be visually recognized from a transparent window provided on the front surface 11a of the pot body 11. This allows the tank 1
The water level in 2, that is, the amount of remaining hot water is known.

An upper part of the tank 12 is opened as a water injection port, and a lid 22 having a rubber packing 21 for closing the opening is provided above the pot body 11 of the electric pot 1. The lid body 22 is detachably pivoted to the pot body 11 by a rear hinge lock mechanism 23, and is openable and closable by a front lock mechanism 24. The electric pot 1 shown in the figure is capable of electric hot water supply by the electric pump 15 and manual hot water supply by an air pump. For this purpose, an air pump including a push-down operation portion 25, a bellows member 26, a valve mechanism 27, etc. is provided in the central portion of the lid body 22. Reference numeral 28 is a fall prevention valve that prevents hot water from leaking outside from the steam holes when the electric pot 1 falls.

An operation panel 29 is provided on the front upper surface of the pot body 11. As shown in FIG. 2, the operation panel 29 includes a display unit 31 and a plurality of push buttons 32 to 36.
Is provided. In addition, a plurality of LED displays (windows) 37
~ 39 are provided. As will be described later in detail, the user of the electric pot 1 can know the hot water temperature in the tank 12 and the time until boiling, etc., by the display on the display unit 31 of the operation panel 29. Further, the push buttons 32 to 36 can be used to instruct hot water supply and set the amount of hot water supply.

The operation panel 29 is provided inside the operation panel 29.
Liquid crystal display and push buttons 32 to 3 corresponding to the display unit 31 of
A first printed circuit board (hereinafter, referred to as a microcomputer board) on which a switch corresponding to 6 and a microprocessor for control are mounted is attached. A printed circuit board (hereinafter referred to as a power supply circuit board) on which a power supply circuit, a drive circuit, etc. are mounted is attached to the bottom of the electric pot 1.

FIG. 3 shows a microcomputer board 40 and a power supply board 4.
FIG. 1 is a block diagram of a main part of an electric circuit including other electric components. The microcomputer board 40 includes a microprocessor (MPU) 42, an A / D converter 43, a waveform shaping circuit 44, a buzzer 46, a reset circuit 47, and an oscillator circuit 4.
8, a switch group 51 corresponding to the push buttons 32 to 36, a switch input circuit 52, a liquid crystal display 53, a plurality of LEDs 5
4 and the display drive circuit 55 are mounted. An electric heater (including a boiling water heater and a heat retention heater) 13, a drive circuit 45 for the electric pump 15, and a power supply circuit 49 are mounted on the power supply board 41.

A temperature sensor 20 for detecting the temperature of the water (hot water) stored in the tank 12 is attached to the outer wall of the tank 12, and the detection signal is converted into a digital value by the A / D converter 43. Is input to the microprocessor 42. Further, as will be described later in detail, the pulse signal output from the flow rate sensor 17 is input to the microprocessor 42 as a rectangular wave signal via the waveform shaping circuit 44.

The drive circuit 45 is a microprocessor 42.
The electric pump 15 and the electric heater 13 are driven by an output signal from the electric pump 15. The drive circuit 45 is configured by using a switching element such as a triac and a relay. The heating capacity of the warming heater of the electric heater 13 and the discharge capacity of the electric pump 15 can be continuously variably controlled by PWM (pulse width modulation) using a switching element or duty ratio control. Electric heater 13
The hot water heater is controlled to be turned on and off using a relay.

The buzzer 46 is a piezoelectric buzzer and is driven by the microprocessor 42 directly or via a drive circuit (not shown). The buzzer 46 sounds when a notification sound such as completion of boiling water, a notification sound of citric acid cleaning time, a push button operation sound, or the like is emitted. Besides, circuit components such as a reset circuit 47 of the microprocessor 42, an oscillation circuit 48 for clock generation, a power supply circuit 49 for supplying a constant DC voltage to the microprocessor 42 and peripheral circuits are mounted.

Next, the structure of the flow sensor 17 will be described. FIG. 4 is a diagram showing the structure of the flow sensor 17,
(A) is a top view and (b) is a sectional view. Flow sensor 1
7 is a printed circuit board (LE) on which an upper case 61, a lower case 62, a rotating member 63, and a light emitting element (LED) 66 are mounted.
D board) 64, a printed circuit board (PD board) 65 on which a light receiving element (PD) 67 is mounted, a cover member 68, and the like.

The upper case 61 is made of transparent resin,
The rotary member 63 is provided with a cylindrical portion and a flange portion 61a protruding from the cylindrical portion. In this collar portion 61a,
Protrusions (not shown) for fixing the LED substrate 64 and the PD substrate 65 are provided. A bearing portion 61b is formed at the center (axis center) portion on the upper end side of the cylindrical portion. The bearing portion 61b is connected to the cylindrical portion by three ribs 61c provided at intervals of 120 degrees.

The lower case 62 is a cylindrical member having a step-shaped cross section that fits on the inner peripheral surface of the lower end portion of the upper case 61 and also fits on the outer peripheral surface of the discharge pipe 16, and its center (axial center). A bearing portion 62a is formed in the) portion. Similar to the bearing portion 61b of the upper case 61, the bearing portion 62a is connected to the inner wall of the lower case 62 by three ribs 62b. The upper case 61 and the lower case 62 are integrated to form a main body case having bearing portions 61b and 62a of a shaft member 69 that rotatably supports the rotating member 63. The upper case 61 is made of transparent resin because it needs to transmit the light emitted from the LED 66, but the lower case 62
May be transparent or opaque.

5A and 5B are views showing the structure of the rotating member 63. FIG. 5A is a view seen from the axial direction, and FIG. 5B is a side view. The rotating member 63 is made of an opaque resin, and includes a cylindrical portion 63a having a through hole HL formed along the axis thereof, and rotating blades 63b and 63c spirally formed around the cylindrical portion 63a. The two rotary blades 63b and 63c form a so-called double spiral shape.

As shown in FIG. 5B, the rotating member 6
The shaft member 69 is inserted into the through hole HL formed in the columnar portion 63a of the shaft 3, and both ends of the shaft member 69 are supported by the bearing portions 61b and 62a of the upper case 61 and the lower case 62. As a result, the rotating member 63 is rotatable about the axis AX. Further, a metal washer 70 is interposed between the bearing portion 61b of the upper case 61 and the tip end side of the rotating member 63 (the upper end side of the cylindrical portion 63a).

As can be seen from FIGS. 4 and 5, an LED (light emitting diode) 66 and a P mounted on the LED substrate 64 are provided.
PD (photodiode) 67 mounted on the D substrate 65
Are arranged so as to face each other, and a straight line (optical path) LT connecting the two is substantially perpendicular to the axis AX of the rotating member 63,
Moreover, it is in a position displaced from the axis AX. Therefore, when the rotary blades 63b and 63c of the rotary member 63 are at the positions shown in FIG. 5B, the light emitted from the LED 66, which is a light emitting element, passes through the transparent upper case 61 and the rotary blade 63b of the rotary member 63. , 63c passing through the gap between
7 is reached (light receiving state).

When the rotary member 63 rotates 90 degrees from the position shown in FIG. 5B, the optical path LT is rotated by the rotary blade 63b or 63.
The light emitted from the LED 66 is PD because it is blocked by c.
67 is not reached (non-light receiving state). In FIG. 4B, 66a is an LED lead line connected to the LED 66 via the wiring pattern of the LED substrate 64, and similarly 67a is a PD lead line connected to the PD 67.
Further, the LED 66 (light emitting element) and the PD 67 (light receiving element) constitute an optical sensor for detecting the rotation speed of the rotating member 63 by the above-described function.

The flow rate sensor 17 having the above structure
Is inserted in the middle of the discharge pipe 16 as shown in FIG. As shown in FIG. 4B, a rubber packing 71 seals the periphery of the portion where the distal end portion of the upper case of the flow sensor 17 and the discharge pipe 16 are joined together. The fitting portion between the lower case 62 and the discharge pipe 16 may be similarly sealed with a rubber packing (not shown) or may be sealed with an adhesive. The flow rate sensor 17 of the present invention is small and lightweight, and may be attached so as to be inserted in the middle of the discharge pipe 16 without being fixed to the main body of the electric pot 1.
In addition, the insertion position in the discharge pipe 16 is preferably above the full water level.

In FIG. 1, when the electric pump 15 is driven and the water (hot water) in the tank 12 flows from the bottom to the top in the discharge pipe 16, when the water passes through the flow rate sensor 17, the spiral rotary blades. 63b and 63c (that is, the rotating member 63) are rotated. This rotation speed is substantially proportional to the speed of the water flow, that is, the flow rate per unit time. Also, the rotary blade 63
When b and 63c rotate, as described above, the light receiving state of FIG. 5B and the non-light receiving state when rotated 90 degrees from that are alternately repeated. As a result, a substantially sinusoidal electric signal that changes between the light receiving level (for example, low level) and the non-light receiving level (for example, high level) is output from the PD 67. The period (frequency) of this substantially sine wave electric signal is
It is proportional to the rotation speed of the rotating member 63.

As will be described later in detail, the substantially sine wave electric signal output from the PD 67 is shaped into a rectangular wave by the waveform shaping circuit 44 of the microcomputer board 40 and is input to the microprocessor 42. The waveform shaping circuit 44 is composed of a comparator, and a rectangular wave in which a transmission potential (for example, low potential) and a light shielding potential (for example, high potential) are alternately repeated by comparing a substantially sinusoidal electric signal with a threshold value. To generate. The microprocessor 42 measures the period or frequency of the rectangular wave by an internal timer,
Calculate the flow rate per unit time.

Next, typical operations and operations of the electric pot 1 of this embodiment will be described together with a fixed amount automatic hot water supply. First, in FIG. 1, the lock mechanism 24 of the lid 22 is released, the lid 22 is opened rearward, and a required amount of water is put into the tank 12. When the lid 22 is closed, the lock mechanism 24 is securely locked, and the plug of the electric cable connected to the electric pot 1 is inserted into the outlet (outlet), the microcomputer board 40 is energized. The microprocessor 42 is reset and starts operating according to the program stored in the built-in ROM. That is, the energization control of the electric heater 13 is started, a predetermined display is performed on the display unit 31 of the operation panel 29 shown in FIG. 2, and the depression of the push buttons 32 to 36 is recognized.

On the operation panel 29 of FIG.
In 1, the multi-digit 7-segment display section displays numerical values such as remaining hot water amount, hot water temperature, and time until boiling. Character displays (“remaining hot water amount”, “temperature”, “after”, “minutes”, “ml”) to indicate which numerical value is displayed are arranged around the 3-digit 7-segment display section and applicable. The character display lights up.

Further, the three triangular marks lined up on the lower side of the 3-digit 7-segment display section are displayed on the lower side of the display section 31 as "98", "90" and "Mahobin". Corresponding, and these show the heat insulation selection state alternatively. When the boiling / heat-retaining button 35 is pressed, the lit triangular marks move in order, and "98", "90" or "mahobin" is selected. "98" or "90"
When is selected, the hot water temperature in the tank 12 is approximately 98 ° C or 90 ° C.
The energization of the electric heater 13 is controlled so as to reach the temperature of ° C.
When "Mahobin" is selected, the electric heater 13 is not energized, and heat is maintained only by the function of the thermos by the tank 12 having the double structure with the vacuum layer sandwiched therebetween. Also,
The boiling LED 39 lights up during "boiling", and the heat retaining LED 38 lights up during "warming".

A good night button 36 is used to set a "good night" timer. When the "good night" timer is set, the "good night" display on the display unit 31 is turned on, and after the set time has elapsed, the heat retention by the energization control of the heater ends.

The hot water supply button 32 that is pressed when hot water is supplied is
To ensure safety, it is valid only for 20 seconds after pressing the unlock button 33. When the lock release button 33 is pressed, the hot water supply LED 37 is turned on and turned off after 20 seconds. Hot water supply button 3 while the hot water supply LED 37 is lit
When 2 is pressed, the electric pump 15 is driven and the discharge port 1
Hot water is discharged from 9. The electric pump 15 is driven only while the hot water supply button 32 is being pressed, and when the finger is released from the hot water supply button 32, the electric pump 15 is stopped and the hot water supply is completed. The electric pot 1 of the present embodiment can also be manually hot-watered by the air pump as described above by pushing down the push-down operation portion 25 provided in the central portion of the lid body 22. A lock lever (not shown) is also provided for the push-down operation unit 25 to ensure safety, and the push-down operation unit 25 can be pushed down after the locked state of the lock lever is released.

As shown in FIG. 2, a hot water supply amount setting button (increase button 34a and decrease button 34b) for setting the hot water supply amount of the automatic fixed amount hot water supply using the flow rate sensor 17 is provided on the operation panel 29. When using the function of the automatic fixed amount hot water supply, a desired amount of hot water supply is set by increasing or decreasing the set amount of hot water supply displayed on the display unit 31 using the hot water supply amount setting buttons 34a and 34b.

Thereafter, the lock release button 33 is depressed, and then the hot water supply button 32 is depressed, as in the case of normal hot water supply. If the hot water supply button 32 is continuously pressed, the electric pump 15 is automatically stopped when the discharge amount of hot water reaches the set hot water supply amount, and the hot water supply ends. That is, the microprocessor 42 of the microcomputer board 40 measures the flow rate per unit time from the output signal of the flow rate sensor 17, as described above,
The discharge amount is calculated by integrating the values. And
The electric pump 15 is stopped when the discharge amount reaches the set hot water supply amount.

Further, in order to ensure safety, if the finger is released from the hot water supply button 32 during the automatic fixed amount hot water supply, the microprocessor 42 causes the microprocessor 42 to discharge even before the discharge amount reaches the set hot water supply amount. Immediately, the electric pump 15 is stopped to finish hot water supply. That is, the continued pressing of the hot water supply button 32 is a necessary condition for the operation of the automatic fixed amount hot water supply.

Further, in FIG. 2, the display character of “citric acid cleaning” on the display unit 31 is the upper case 61 of the flow rate sensor 17.
(That is, the light is turned on when notifying the proper time to carry out the citric acid cleaning in order to eliminate the stain on the inner wall of the transparent tube). For example, the usage time of the electric pot 1 is added to the nonvolatile memory built in or attached to the MPU 42,
When the accumulated value reaches the desired value, the display character of "citric acid cleaning" is turned on. Alternatively, as will be described later, the degree of dirt on the inner wall of the upper case 61 may be estimated based on the signal output from the PD 67 of the flow rate sensor 17, and the display character of “citric acid cleaning” may be turned on.

FIG. 6 is a circuit diagram showing an example of a flow rate detection circuit including the flow rate sensor 17 and the waveform shaping circuit 44. The LED 66, which is a light emitting element of the flow rate sensor 17, is connected between the power supply voltage VDD and the ground potential via the current limiting resistor R1 and is driven by a predetermined current. Also, the flow sensor 1
The PD 67, which is the light receiving element of No. 7, is connected between the ground potential and the power supply voltage VDD via the sensitivity adjusting resistor R2.

In the circuit example of FIG. 6, if the resistance value of the current limiting resistor R1 is reduced, the current flowing through the LED 66 increases and the intensity of light emitted from the LED 66 increases. Also,
The sensitivity increases as the resistance value of the sensitivity adjusting resistor R2 increases, and the amplitude of the substantially sine-wave electric signal (voltage waveform) output from the PD 67 increases. This substantially sinusoidal electric signal becomes an input voltage signal of the comparator 44 a of the waveform shaping circuit 44. A reference voltage (threshold value) Vref obtained by dividing the power supply voltage VDD by the resistors R3 and R4 is input to the reference voltage terminal of the comparator 44a. The output signal of the comparator 44a is M as a rectangular wave after waveform shaping.
It is input to the PU 42.

FIG. 7 is a waveform diagram showing a first example of a substantially sinusoidal voltage waveform output from the PD 67 and a rectangular wave after waveform shaping. (A) shows a conventional threshold value Vref of about 2.5.
FIG. 9B shows a case where the threshold voltage Vref is set to V, and FIG. 9B shows a case where the threshold value Vref is set to approximately 4V in this embodiment.

In the conventional case shown in FIG. 7 (a), the substantially sinusoidal voltage waveform (before waveform shaping) output from the PD 67 in the initial use of the electric pot is substantially between 0V and 5V as shown by the solid line. It is changing evenly. In the rectangular wave after waveform shaping obtained by comparing the substantially sinusoidal voltage waveform with the threshold value Vref = 2.5V, the 0V period and 5V are applied.
The period and are repeated almost equally.

However, when the usage period becomes long and the inner wall of the upper case 61 (transparent tube) of the flow sensor 17 becomes dirty, the light transmittance decreases and the light receiving amount of the PD 67 decreases. As a result, in the substantially sine-wave voltage waveform output from the PD 67, the potential on the 0 V side (transmission potential side) rises and approaches the intermediate potential as shown by the broken line. Then, the 0V period of the rectangular wave after the waveform shaping becomes narrow as shown by the broken line, and a phenomenon (pulse omission) occurs where the 0V period disappears at the place where it should be. In the place where the pulse dropout occurs,
As shown in (a), the original period T is erroneously measured as twice T '. Alternatively, erroneous measurement occurs in which the frequency, which is the number of pulses per unit time, becomes smaller (lower) than the original value.

On the other hand, in the case of this embodiment shown in FIG. 7B, the threshold value Vref is the intermediate level (2.5 V).
Is set to about 4V which is 5V side (light shielding potential side). For this reason, in the rectangular wave after waveform shaping at the initial stage of use, the 0V period is longer than the 5V period. However, the repetition cycle T is the same as in the case of FIG. 7A, and the cycle or frequency can be measured without any problem.

As in the case of FIG. 7A, when the amount of light received by the PD 67 decreases as the usage period increases, the PD 6
In the substantially sinusoidal voltage waveform output from 7, the potential on the 0 V side (transmission potential side) rises and approaches the intermediate potential as shown by the broken line. However, the rectangular wave after waveform shaping obtained by comparing with the threshold value Vref = 4V hardly changes from the initial use state of the solid line as shown by the broken line, and the above-mentioned pulse omission phenomenon does not occur. Therefore, FIG.
In the case of this embodiment shown in FIG. 7, the period (life) in which the flow sensor 17 can be normally used becomes longer than in the conventional case shown in FIG.

FIG. 8 is a waveform diagram showing a second example of a substantially sine-wave voltage waveform output from the PD 67 and a rectangular wave after waveform shaping. (A) shows that the voltage waveform having a substantially sine wave is from 0V to 5
Shown is the conventional case in which V changes substantially evenly,
(B) shows the case of this embodiment.

In the case of the conventional case shown in FIG.
As described with reference to (a), an ideal waveform signal (solid line) is obtained in the initial stage of use of the electric pot, but when the inner wall of the upper case 61 (transparent tube) of the flow sensor 17 becomes dirty, it becomes a broken line. The waveform is changed to that shown in Fig. 3 and a pulse omission phenomenon occurs in the rectangular wave after waveform shaping. As a result, the original cycle T is erroneously measured as T ′ at the place where the pulse dropout occurs, or erroneous measurement occurs in which the frequency, which is the number of pulses per unit time, is smaller (lower) than the original value.

In the case of the present embodiment shown in FIG. 8B, P
The substantially sinusoidal voltage waveform output from D67 is saturated on the 0V side (transmission potential side) at the initial use of the electric pot as shown by the solid line, and the period on the 0V side from the intermediate level (2.5V) is the 5V side. It is set to be longer than the period of (light shielding potential side). That is, the rectangular wave after waveform shaping has a 0V period longer than the 5V period as shown in FIG. 8B. For this reason, even if the threshold value Vref is set to the intermediate level (2.5 V) as in the conventional case of FIG. 8A, the inner wall of the upper case 61 (transparent tube) of the flow sensor 17 becomes dirty. Accordingly, it is possible to delay the time when the level of the transmission potential side of the substantially sine wave voltage waveform approaches the intermediate level. That is, as shown by the broken line, even if the level on the transmission potential side rises from 0 V, the time required to reach the intermediate level is as shown in FIG.
It is longer than in the case of (a). In other words, FIG.
In the case of the present embodiment shown in FIG. 8B, the period (life) during which the flow sensor 17 can be normally used becomes longer than in the conventional case shown in FIG. 8A.

As described above, the upper case 6 of the flow sensor 17
When the inner wall of No. 1 (transparent tube) becomes dirty, the light transmittance decreases and the amount of light received by the PD 67 decreases, but this state is resolved by performing a cleaning and boiling maintenance called citric acid cleaning. .

When the electric pot 1 is used for a long period of time, components such as calcium carbonate and magnesium carbonate contained in water are deposited on the inner wall of the tank 12, and the inside of the tank gradually becomes white. Moreover, when this deposit peels off and enters the inside of the electric pump 15, the electric pump 15 is clogged,
It may cause malfunction.

Therefore, when the inner wall of the tank 12 becomes extremely dirty, or the citric acid cleaning is performed at regular intervals, it is recommended to the user by the instruction manual or the like. In the citric acid cleaning, citric acid sold as a consumable item for maintenance by the manufacturer of the electric pot is put into the tank 12 together with water and boiled for a predetermined time. In the electric pot 1 of the present embodiment, the citric acid cleaning mode is executed by simultaneously pressing the sleep button 36 and the boiling / heat retaining button 35 on the operation panel 29. In the citric acid cleaning mode, the energization of the heater is stopped after the boiling state is continued for a predetermined time.

As described above, the citric acid cleaning mode is originally performed for the purpose of removing dirt (precipitate) on the inner wall of the tank 12 and avoiding the malfunction of the electric pump 15. However, the citric acid cleaning also cleans the dirt on the inner wall of the upper case 61 (transparent tube) of the flow rate sensor 17, and the substantially sinusoidal voltage waveform output from the PD 67 of the flow rate sensor 17 is restored to the initial state of use. next,
A process of notifying the user of the time when the citric acid cleaning should be performed based on the substantially sinusoidal voltage waveform output from the PD 67 of the flow rate sensor 17 will be described.

FIG. 9 is a circuit diagram showing a second example of the flow rate detection circuit including the flow rate sensor 17 and the waveform shaping circuits 44A and 44B. In this example, two waveform shaping circuits 44A, 4A
4B is used to obtain two rectangular waves A and B. The first waveform shaping circuit 44A is configured by using a comparator 44Aa, and its reference voltage (first threshold value) Vref1 is set to about 4V like the reference voltage in the circuit example shown in FIG. There is. The second waveform shaping circuit 44B is composed of a comparator 44Ba, and its reference voltage (second threshold value) Vref2 is set to about 1V by the voltage dividing resistors R5 and R6. That is, the second threshold V
ref2 is set to be closer to 0 V side (transmission potential side level) than the first threshold value Vref1.

FIG. 10 shows PD6 in the circuit example of FIG.
7 is a waveform diagram showing a first example of a substantially sinusoidal voltage waveform output from FIG. 7 and a rectangular wave after waveform shaping. FIG. A first rectangular wave is given to the MPU 42 from the first waveform shaping circuit 44A,
A second rectangular wave is output from the second waveform shaping circuit 44B to the MPU4.
Given to 2.

As shown by the solid line in FIG. 10, the voltage waveform of the substantially sine wave output from the PD 67 in the initial use of the electric pot changes substantially uniformly between 0V and 5V. Therefore, the first rectangular wave after waveform shaping becomes a rectangular wave having a period T in which the 0V period is longer than the 5V period, and the second rectangular wave becomes a rectangular wave in the period T having a 0V period shorter than the 5V period. When the amount of light received by the PD 67 decreases as the usage period of the electric pot increases, the potential of the substantially sinusoidal voltage waveform output from the PD 67 increases on the 0 V side (transmission potential side) as indicated by the broken line, and Vref2 Approaching. At this time, the first rectangular wave hardly changes, but as for the second rectangular wave, the 0V period is further shortened as shown by the broken line, and the 0V period disappears at a position where it should be (pulse loss).
At the place where the pulse dropout occurs, the original cycle T is erroneously set to 2
It will be erroneously measured as double T '. Alternatively, erroneous measurement occurs in which the frequency, which is the number of pulses per unit time, becomes smaller (lower) than the original value.

Therefore, in this example, the discharge amount is measured using the first rectangular wave as in the example described with reference to FIGS. 6 and 7, but the citric acid cleaning is further performed using the second rectangular wave. A process is performed to determine when to implement and notify the user. Specifically, as described below, the frequencies (the number of pulses per unit time) of the first rectangular wave and the second rectangular wave are compared, and when the ratio of both is 2 or more, the notification is performed.

FIG. 11 is a flow chart showing a first example of the processing for judging the time when the citric acid cleaning should be carried out and notifying the user. When the hot water supply is started, the MPU 42 drives the pump in step # 101,
In 2, the number of pulses of the first rectangular wave is counted. Let the count value be A. Similarly, in step # 103, the number of pulses of the second rectangular wave is counted, and the count value is set to B.

At step # 104, the amount of hot water supply is displayed, and at step # 105, it is determined whether or not the amount of hot water supply has reached the set value. That is, the pulse number A of the first rectangular wave
From step # 101 until step #
If the set value is reached by repeating the process of 105, the pump is stopped in step # 106.

Next, in step # 107, the pulse number A of the first rectangular wave and the pulse number B of the second rectangular wave are compared. If B is less than half of A, it means that the pulse omission of the second rectangular wave is 1/2 or more as described with reference to FIG. Otherwise, step # 10
In 8, the hot water supply completion is informed by, for example, two beeps, and in step # 109, the hot water supply amount is displayed and the process ends normally.

If B is less than half of A in step # 107, hot water supply warning is given by, for example, three beeps in step # 110. This notification means that the time when the flow rate sensor 17 cannot accurately measure the discharge amount due to dirt is approaching. Then, in step # 111, the amount of hot water supply is displayed, and in step # 112, the display of “citric acid cleaning” is turned on and the process ends. As described above, the display of “citric acid cleaning” is provided on the display unit 31 of the operation panel 29 and is turned on to notify the user that it is time to carry out citric acid cleaning.

FIG. 12 shows the PD6 in the circuit example of FIG.
7 is a waveform diagram showing a second example of a substantially sinusoidal voltage waveform output from FIG. 7 and a rectangular wave after waveform shaping. Similar to the first example shown in FIG. 10, the PD 6 is used at the initial use of the electric pot.
The substantially sinusoidal voltage waveform output from 7 changes almost uniformly between 0V and 5V as shown by the solid line. Therefore, the first rectangular wave after waveform shaping becomes a rectangular wave whose 0V period (pulse width W1) is longer than 5V period, and the second rectangular wave becomes a rectangular wave whose 0V period (pulse width W2) is shorter than 5V period.

When the amount of light received by the PD 67 decreases as the usage period of the electric pot increases, the substantially sinusoidal voltage waveform output from the PD 67 rises in potential on the 0 V side (transmission potential side) as indicated by the broken line. Then, it approaches Vref2. At this time, the first rectangular wave hardly changes, but the second rectangular wave has a 0 V period (pulse width W
2 ') becomes even shorter.

Therefore, in this example, the ejection amount is measured using the first rectangular wave as in the example described with reference to FIGS. 6 and 7, but the citric acid cleaning is further performed using the second rectangular wave. A process is performed to determine when to implement and notify the user. Specifically, as described below, the pulse widths (0 V period) of the first rectangular wave and the second rectangular wave are compared, and if the ratio of the two is greater than or equal to a predetermined value, notification is performed.

FIG. 13 is a flow chart showing a second example of the processing for judging the time when the citric acid cleaning should be carried out and notifying the user. When the hot water supply is started, the MPU 42 drives the pump in step # 201,
2, the pulse width W1 of the first rectangular wave is measured, and the average value W thereof is obtained. Similarly, in step # 203, the second
The pulse width W2 of the rectangular wave is measured and the average value w thereof is obtained. Further, in step # 204, the number of pulses of the first rectangular wave is counted, and the count value is set to A.

In step # 205, the hot water supply amount is displayed, and in step # 206, it is determined whether or not the hot water supply amount has reached the set value. That is, the pulse number A of the first rectangular wave
Until step # 201 to step #
When the set value is reached by repeating the process of 206, the pump is stopped in step # 207.

Next, in step # 208, the average value W of the pulse widths of the first rectangular wave and the average value w of the pulse widths of the second rectangular wave are compared. When w is greater than 1/3 of W,
In step # 209, the hot water supply completion notification is given by, for example, two beeps, and in step # 210, the hot water supply amount is displayed and the processing ends normally. However, in this example, w is set to about ½ or more of W in the initial use of the electric pot, and if w is ⅓ or less of W, it is time to perform citric acid cleaning. I will inform you.

That is, when it is determined in step # 208 that w is ⅓ or less of W, it is further determined in step # 211 whether w is ⅕ or less of W. If w is between ⅓ and ⅕ of W (No in step # 211), hot water warning is given by, for example, three beeps in step # 212. This notification means that the time when the flow rate sensor 17 cannot accurately measure the discharge amount due to dirt is approaching, and informs the user that citric acid cleaning should be performed at the earliest possible time. Then, in step # 213, the hot water supply amount is displayed, and in step # 214, the display of "citric acid cleaning" is turned on and the process is ended.

When w is 1/5 or less of W (Yes in step # 211), the hot water supply warning is issued in step # 215 by, for example, eight beeps. This notification informs the user that if the citric acid cleaning is not performed immediately, the flow rate sensor 17 cannot accurately measure the discharge amount due to dirt. After this step #
The amount of hot water supplied is displayed in 216, and "citric acid cleaning" is displayed in blinking in step # 214, and the process ends.

Although the embodiment of the present invention has been described above, the present invention is not limited to the above embodiment and can be implemented in various forms.

For example, in the above embodiment (FIG. 6), the output signal of the flow rate sensor 17 (PD67) is applied to the waveform shaping circuit 44.
The waveform is shaped by the (comparator 44a) and then input to the microprocessor 42. However, if a microcomputer with a built-in comparator is used, the output signal of the flow rate sensor 17 can be directly input to the microcomputer. In this case, the reference voltage (threshold value) of the comparator can be set by the program of the microcomputer. Since the set value can be dynamically changed by a program, it is possible to obtain a plurality of rectangular waves after waveform shaping by using a plurality of threshold values as in the circuit example of FIG.

Alternatively, it is also possible to directly input the output signal of the flow rate sensor 17 to the microcomputer by using the microcomputer having the built-in A / D converter. In this case, the digital data obtained by reading the output signal of the flow rate sensor 17 at a predetermined sampling cycle is compared with a threshold value by software, and the repetition cycle or frequency of the transmission state and the light blocking state is obtained.

In the above embodiment, by adjusting the resistance values of the current limiting resistor of the light emitting element of the flow sensor and the sensitivity adjusting resistor of the light receiving element, a substantially sinusoidal electric signal output from the light receiving element is adjusted. The level on the transmission potential side was saturated in the initial stage of use of the electric pot, and the period on the transmission potential side from the intermediate level was set to be longer than the period on the light shielding potential side. As another method, for example, by adjusting the angle between the optical axis from the light emitting element to the light receiving element of the flow sensor and the axis of the spiral rotary blade (tilting from 90 degrees),
Alternatively, the substantially sinusoidal electric signal output from the light receiving element may be set as described above by adjusting the twist angle of the spiral rotary blade.

Further, the contents of buzzer sound and display for notifying the user that it is time to carry out the citric acid cleaning can be appropriately changed. The method of comparing the number of pulses and the pulse width and the threshold value thereof exemplified in the process for determining the timing are not limited to the examples in the above embodiment, and may be appropriately changed.

[0084]

As described above, according to the present invention, the erroneous measurement of the discharge amount due to the contamination of the inner wall of the transparent tube forming the flow sensor can be avoided, and the life of the flow sensor can be extended. In addition, it is possible to accurately judge the timing of carrying out the citric acid cleaning that can eliminate the stain on the inner wall of the transparent tube and notify the user.

[Brief description of drawings]

FIG. 1 is a sectional view of an electric pot according to an embodiment of the present invention.

FIG. 2 is a plan view of an operation panel.

FIG. 3 is a block diagram of a main part of an electric circuit.

4A and 4B are views showing a structure of a flow rate sensor, FIG. 4A is a top view and FIG. 4B is a sectional view.

5A and 5B are views showing a structure of a rotating member, FIG. 5A is a view seen from an axial direction, and FIG. 5B is a side view.

FIG. 6 is a circuit diagram showing an example of a flow rate detection circuit including a flow rate sensor and a waveform shaping circuit.

FIG. 7 is a waveform diagram showing a first example of a substantially sinusoidal voltage waveform output from a PD (light receiving element) and a rectangular wave after waveform shaping, (a) showing a conventional case, and (b). Shows the case of the present embodiment.

FIG. 8 is a waveform diagram showing a second example of a substantially sinusoidal voltage waveform output from a PD (light receiving element) and a rectangular wave after waveform shaping, (a) showing a conventional case, and (b). Shows the case of the present embodiment.

FIG. 9 is a circuit diagram showing an example of a flow rate detection circuit including a flow rate sensor and a waveform shaping circuit.

10 is a waveform diagram showing a first example of a substantially sinusoidal voltage waveform output from a PD and a rectangular wave after waveform shaping in the circuit example of FIG. 9.

FIG. 11 is a flowchart showing a first example of a process of determining when to perform citric acid cleaning and notifying the user.

FIG. 12 is a waveform diagram showing a second example of a substantially sinusoidal voltage waveform output from the PD and a rectangular wave after waveform shaping in the circuit example of FIG. 9.

FIG. 13 is a flowchart showing a second example of a process of determining when to carry out citric acid cleaning and notifying the user.

[Explanation of symbols]

1 electric pot 12 tanks 13 heater 15 Electric pump 16 discharge pipe 17 Flow sensor 19 outlets 29 Operation panel 31 Display 42 Control unit (microprocessor) 61 Transparent tube (upper case) 63 rotating member 63b, 63c rotary vanes 66 Light emitting element (LED) 67 Photodetector (PD) AX axis

Continuation of front page (56) Reference JP-A-2002-238763 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) A47J 27/21 101 G01F 1/00 G01F 1/115

Claims (3)

(57) [Claims] 1. A heater and a tank for heating water,
An electric pump and a discharge pipe for discharging the hot and cold water in the tank to the outside, a flow rate sensor inserted in the discharge path, and a control unit for measuring the discharge rate of the hot and cold water based on the output signal of the flow rate sensor. An electric pot with a flow sensor, wherein the flow sensor comprises a rotating member having rotating blades that rotate around an axis along a flowing direction of hot water in the transparent tube, and the transparent member disposed outside the transparent tube. A light emitting element and a light receiving element for irradiating light toward the rotary blade in the tube are included, and the light emitted from the light emitting element passes through the gap of the rotary blade to the light receiving element as the rotating member rotates. By alternately repeating the arriving transmission state and the light-shielding state in which the light emitted from the light emitting element is blocked by the rotary vanes and does not reach the light receiving element, the light receiving element is substantially positive. A chordal electric signal is obtained, and the control unit corresponds to the transmission state by comparing a substantially sinusoidal electric signal output from the light receiving element of the flow sensor with a threshold value. It is configured to generate a rectangular wave in which a transmission potential and a light-shielding potential corresponding to the light-shielding state are alternately repeated, and obtain the discharge amount of the hot water from the cycle or frequency of the rectangular wave. The electric signal with a flow sensor is characterized in that the level of the transmission potential side of the substantially sine wave electric signal is saturated, and the period of the transmission potential side of the intermediate level is longer than the period of the light shielding potential side. pot. 2. A heater and a tank for heating water,
An electric pump and a discharge pipe for discharging the hot and cold water in the tank to the outside, a flow rate sensor inserted in the discharge path, and a control unit for measuring the discharge rate of the hot and cold water based on the output signal of the flow rate sensor. An electric pot with a flow sensor, wherein the flow sensor comprises a rotating member having rotating blades that rotate around an axis along a flowing direction of hot water in the transparent tube, and the transparent member disposed outside the transparent tube. A light emitting element and a light receiving element for irradiating light toward the rotary blade in the tube are included, and the light emitted from the light emitting element passes through the gap of the rotary blade to the light receiving element as the rotating member rotates. By alternately repeating the arriving transmission state and the light-shielding state in which the light emitted from the light emitting element is blocked by the rotary vanes and does not reach the light receiving element, the light receiving element is substantially positive. A chordal electric signal is obtained, and the control unit corresponds to the transmission state by comparing a substantially sinusoidal electric signal output from the light receiving element of the flow sensor with a threshold value. It is configured to generate a rectangular wave in which a transmission potential and a light-shielding potential corresponding to the light-shielding state are alternately repeated, and obtain the water discharge amount from the cycle or frequency of the rectangular wave, wherein the threshold value is An intermediate level of the change range of the substantially sinusoidal electric signal output from the light receiving element is set to a level closer to the light shielding potential side than the intermediate level of the change range of the substantially sinusoidal electric signal output from the light receiving element. In addition to the first threshold value set closer to the level on the light-shielding potential side than the first threshold value, a second threshold value set to the level closer to the transmission potential side than the first threshold value, The control unit The period or frequency of the first rectangular wave generated using the first threshold value and the second rectangular wave generated using the second threshold value are compared, and the first rectangular wave and An electric pot with a flow sensor, wherein predetermined notification is given when the difference in the cycle or frequency of the second rectangular wave becomes larger than a predetermined value. 3. A heater and a tank for heating water,
An electric pump and a discharge pipe for discharging the hot and cold water in the tank to the outside, a flow rate sensor inserted in the discharge path, and a control unit for measuring the discharge rate of the hot and cold water based on the output signal of the flow rate sensor. An electric pot with a flow sensor, wherein the flow sensor comprises a rotating member having rotating blades that rotate around an axis along a flowing direction of hot water in the transparent tube, and the transparent member disposed outside the transparent tube. A light emitting element and a light receiving element for irradiating light toward the rotary blade in the tube are included, and the light emitted from the light emitting element passes through the gap of the rotary blade to the light receiving element as the rotating member rotates. By alternately repeating the arriving transmission state and the light-shielding state in which the light emitted from the light emitting element is blocked by the rotary vanes and does not reach the light receiving element, the light receiving element is substantially positive. A chordal electric signal is obtained, and the control unit corresponds to the transmission state by comparing a substantially sinusoidal electric signal output from the light receiving element of the flow sensor with a threshold value. It is configured to generate a rectangular wave in which a transmission potential and a light-shielding potential corresponding to the light-shielding state are alternately repeated, and obtain the water discharge amount from the cycle or frequency of the rectangular wave, wherein the threshold value is An intermediate level of the change range of the substantially sinusoidal electric signal output from the light receiving element is set to a level closer to the light shielding potential side than the intermediate level of the change range of the substantially sinusoidal electric signal output from the light receiving element. In addition to the first threshold value set closer to the level on the light-shielding potential side than the first threshold value, a second threshold value set to the level closer to the transmission potential side than the first threshold value, The control unit The pulse widths of the first rectangular wave generated using the first threshold value and the second rectangular wave generated using the second threshold value are compared, and the first rectangular wave and the first rectangular wave An electric pot with a flow sensor, wherein predetermined notification is given when the difference between the pulse widths of two rectangular waves becomes larger than a predetermined value.