JPH0321698Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an electric water heater equipped with a microcomputer that electronically controls a boiling heater.

[Prior Art and Problems] Various kinds of electric water heaters have been known in the past, and some are equipped with a reboiling circuit or a heat retention circuit for controlling a boiling heater.

Incidentally, in recent years, with the spread of microcomputers, electric water heaters have appeared that can electronically control the transition from boiling to warming, detection of insufficient water volume, stopping boiling during empty cooking, and the like.

However, since electric water heaters store liquid in a container, there is always a risk of liquid leakage. Therefore, if liquid leakage should occur, there is a risk of damaging the microcomputer. In other words, in the case of a water heater equipped with a conventional analog electric circuit, if there is a leak in the container, it can be reused by repairing the container, but in the case of an electric water heater with a built-in electronic control device as described above, ,
If the liquid leaking from the container enters the microcomputer, the microcomputer will be damaged, and the container cannot be reused by simply repairing it, making it unnecessary to replace the electronic parts.
Although the above problem can be solved by assembling all electronic components including the microcomputer in a watertight manner, this poses a new problem in that the assembling work becomes extremely complicated.

[Means for Solving the Problems] The present invention provides an electric water heater that solves the above-mentioned problems, and the means thereof consists of a container 3 equipped with a boiling heater 5 and an outer periphery of the container. a cylindrical case 4 surrounding the case, a bottom member 12 provided at the bottom of the case, a heater power control circuit 93 for controlling the heater, and a microcomputer 77 for providing a heater control signal to the heater power control circuit. The container 3 comprises:
A bracket 74 is provided protruding from the bottom part; the bottom member 12 is integrally formed with a cylindrical mounting part 65 with upper and lower openings into which the bracket 74 is inserted, and a housing part 64 which closes the upper part and opens the lower part. death,
Electronic components including the microcomputer are housed in the housing part 64; a bottom cover plate 75 superimposed on the lower surface of the bottom member 12 is screwed to the bracket 74 via the attachment part 65; The bottom member 12 is sandwiched between the bottom cover plate 75 and the case 4, and the bottom opening of the housing portion 64 is closed by the bottom cover plate 75.

〔Example〕

An embodiment of the present invention will be described in detail below based on the drawings.

(Overall Configuration) As shown in FIGS. 1 to 3, the electric water heater consists of a container body 1 and a lid body 2.

The container body 1 includes a bottomed cylindrical container 3 made of a thin stainless steel plate or the like with an open top, and a cylindrical case 4 made of a thin metal plate or the like surrounding the outer periphery of the container 3 at intervals. The container 3 is equipped with an electric boiling heater 5 on the outer periphery near the bottom, and a water pumping port 6 is provided near the bottom of the container 3 (bottom bottom surface or bottom peripheral surface). A shoulder member 7 is attached to the upper part of the container body 1, and the shoulder member 7 is integrally molded from synthetic resin, connects the upper ends of the container 3 and the case 4, and has a pivot portion of the lid body 2, which will be described later, on the back side. 8 and a beak 9 on the front. A decorative member 10 is connected to the lower part of the beak 9,
A transparent window portion 11 extending vertically in the decorative member 10
is formed. On the other hand, at the bottom of the container body 1,
A bottom member 12 made of synthetic resin is attached.

The water pumping port 6 of the container 3 is communicated with a water filling port 13 opened at the lower part of the beak 9 of the shoulder member 7 via a pumping channel 14. In the illustrated example, the lower end of the liquid level display tube 15 arranged corresponding to the window 11 is connected via an elbow tube 17 to a mouth tube 16 fixed to the water pumping port 6 of the container 3 by welding or the like. There is. Further, the upper end of the liquid level display tube 15 is connected to a spout 18 that holds the water inlet 13 via an elbow tube 19, and the spout 18 and the water inlet 13 are covered by the beak 9. ing. In the illustrated example, a valve chamber 20 is provided between the elbow tube 19 and the upper end of the liquid level display tube 15.
is formed, and a valve body 21 is inserted into the valve chamber. A narrow passage is formed between the outer periphery of the valve body 21 and the inner periphery of the valve chamber 20 by ribs in the radial direction. When the hot water is forced into the pumping channel 14, the hot water is sent to the spout 18 through the narrow passage formed by the ribs and is discharged from the water inlet 13. On the other hand, when the air pot falls over, the valve body 21 moves within the valve chamber 20 and closes the end opening of the elbow tube 19, so that the hot water in the container 3 flows into the pumping channel 1.
This prevents a large amount of water from leaking from the water inlet 13 via the water inlet 13 through the water injection port 13.

The lid main body 2 is formed into a hollow block body by a synthetic resin bowl-shaped base 22 that is loosely fitted into the shoulder member 7, and a head 23 that covers the upper part of the base 22. is pivotally supported on a pivot portion 8 of the shoulder member 7 via a pivot shaft 8a. Therefore, the axis 8a
The lid main body 2 is rotatable about the fulcrum, and thereby the upper opening of the container main body 1 can be opened and closed. Note that a locking/disengaging mechanism 25a is provided on the front side of the lid body 2, and the lid body 2 is connected to and disconnected from the shoulder member 7 while the lid body 2 is attached to the container body 1.

A bellows-type air pump 26 is installed on the base 22 of the lid body 2, and the cylindrical lower edge of the air pump is fixed to the base 22, and the periphery of the actuating member 24 is fixed to the cylindrical upper edge. . The actuating member 24 forms a guide cylinder part 24b that projects into the air pump, and a valve cylinder 25 is slidably inserted into the guide cylinder part 24b. The lower end of the valve cylinder 25 is the base 2
A switching valve 27 made of an elastic body is provided at the insertion end of the valve 27, which is made of an elastic body and expands to a large diameter below the exhaust port 26a. Inside the air pump 26, a pump return member 28 made of a compression coil spring is interposed between the base 22 and the operating member 24, and is always biased in a direction to push up the operating member 24 and expand the air pump 26. are doing.
The valve cylinder 25 is provided with a locking part 29 that is locked in an extended state with respect to the guide cylinder part 24b, and the switching valve 27 is connected to the exhaust port 2 when the air pump 26 is expanded.
6a.

An actuation button 31 is slidably inserted into an opening cylindrical portion 30 located above the actuation member 24 and opened in the head 23 . When the locking pawl 32 formed on the outer peripheral edge of the lower end of the operating button 31 is engaged with the lower edge of the opening cylindrical portion 30, the top surface of the operating button 31 is substantially flush with the top surface of the head 23. , the actuation button 31 does not protrude upward any further. On the other hand, a lock member 33 is rotatably fitted on the outer periphery of the open cylindrical portion 30, and when the lock member 33 is rotated in one direction via a knob 33a, the lower end of the lock member 33 is locked. The pawl can be locked onto the lower surface of the locking pawl 32 of the actuation button 31, thereby making it impossible to press down the actuation button 31.
On the contrary, when the locking member 33 is rotated in the other direction,
The locking of the pawl is released so that the actuation button 31 can be pressed. A receiving part 34 is formed at the lower part of the operating button 31, and the receiving part 34
and the bottom of the valve cylinder 25, the pump return member 2
A button return member 35 made of a compression coil spring with a spring constant smaller than that of 8 is interposed, and the button return member 35 is inserted so that the operating button 31 is always
is biased upward. In this state, the intake valve 36 made of an elastic body and attached to the lower end of the receiving part 34 is positioned at a distance above the upper opening edge of the guide cylinder part 24b.

The exhaust port 26a is communicated with an air supply port 38 that opens near the top of the container 3 via an air supply path 37. Further, the air supply path 37 is communicated with an outside air port 40 opened in the head 23 via a steam path 39 . In the illustrated example, an air passage member 41 that forms the valve chamber of the switching valve 27 is attached to the lower surface of the base 22, and the air passage member 41 provides a port 42 located at the lower center of the valve chamber. 42 and defines the air supply passage 37 communicating with the valve chamber, while defining a branch passage 43 extending from the port 42 to the steam passage 39. The branch road 42 is
The cylinder part 22a is connected to the cylinder part 22a formed in the base 22 through the pipe material, and the cylinder part 22a is connected to the cylinder part forming the outside air port 40 through the pipe material, so that the branch passage 43 is A steam path 39 leading to the outside air port 40 is configured.

A protection plate 44 made of a thin stainless steel plate or the like is provided to cover the flow path member 41 and the pipe material constituting the steam path 39 from below, and is fixed to the bottom of the base 22 with screws. In addition, in the figure, 45 is arranged to straddle the upper part of the lid body 2, and both ends are connected to the container body 1.
It is a handle that is pivoted to.

To explain the action based on the valve mechanism, the container 3
While the water in the tank is being boiled, water is not injected, so the air pump 26 is not operated. When the pump is not operating, the pump return member 28 is extended and the operating member 24 is extended as shown in the first figure.
is pushed up, thereby lifting the valve cylinder 25 that is locked at the locking portion 29, and the switching valve 27 closes the exhaust port 26a of the air pump. Therefore, the boiling steam that has entered the air supply path 37 from the air supply port 38 is discharged from the exhaust port 26a.
The air will not enter the air pump 26 from outside.
In this state, the switching valve 27 is switched to the port 4 of the branch passage 43.
2 is opened to open communication between the air supply passage 37 and the steam passage 39, the boiling steam that enters the air supply passage 37 passes through the steam passage 39 and is discharged into the outside air from the outside air port 40. Therefore, the pressure generated when the water in the container 3 boils is suitably reduced by the path from the air supply port 38 to the outside air port 40 via the steam path 39.

On the other hand, while the hot water in the container 3 is kept at a predetermined temperature after boiling, the hot water can be poured by the air pump 26. That is, the air pump 26
When air is pumped into the container 3 by operating the
The water is poured out from the water inlet 13 through the water inlet. The air pump 26 is operated by pushing the operating button 31 into the open cylindrical portion 30 of the head 23. When the air pump is operated, as shown in the second figure, when the operating button 31 is lowered against the button return member 35, the locking pawl 32 comes into contact with the operating member 24, and the operating member 24 is simultaneously lowered against the pump return member 28 to compress the air pump 26. At this time, the intake valve 36 is connected to the intake opening 24 formed at the upper part of the guide cylinder portion 24b of the actuating member 24.
On the other hand, the valve cylinder 25 is lowered via the button return member 35, and the switching valve 27 is closed to the exhaust port 26.
a is opened, and the port 41 of the branch path 43 is closed. Therefore, the air discharged from the exhaust port 26a due to the compression of the air pump 26 flows through the steam path 3.
The air does not enter the air passageway 9 and leak, and is suitably fed under pressure into the container 3 through the air passageway 37 and through the air supply port 38 . Note that when repeatedly operating the air pump 26, the operating button 31 is released from the pushing force, and the operating button 31 is returned to the air pump 2 by the button return member 35.
When the air pumps 6 are returned to their original positions by the pump return members 28, the intake valves 36 unblock the intake openings 24a, so that outside air is sucked into the air pumps 26 through the clearances between the members.

(Control mechanism and circuit) Thermistors 46 and 47 as temperature detectors are installed near the opening and at the bottom of the container 3, respectively.
is provided.

Further, a water amount detection section 48 is provided at a position of the liquid amount display cylinder 15 corresponding to a liquid amount shortage. The water amount detection unit 48 includes a pair of electrodes 48a and 48b that sandwich the liquid amount display barrel 15 from the outer circumferential side, and electrically insulates both the electrodes 48a and 48b, respectively, and also electrically insulates the two electrodes 48a and 48b. , 48b are covered and surrounded by a cylindrical shield body.

A pocket portion 49 is formed by recessing the outer surface of the beak portion 9, and although not shown, the pocket portion 49 includes a boiling and heat retention indicator light 50 consisting of a light emitting diode, which will be described later. A water shortage and timer operation indicator light 51 consisting of a diode, a boil command switch 52, and a timer set switch 53 are installed inside. These indicator lights 5
0 and 51 and switches 52 and 53 are installed in advance on an insulating substrate, and this substrate is inserted into the pocket portion 49.

The electronic control circuit is as shown in FIG. The one-chip microcomputer 77 has a CPU 78,
ROM79, RAM80, input/output port 81,
82, 83, 84, 85, 86, 87, etc., including a water shortage detection circuit 88, a power frequency synchronization pulse generation circuit 89, a temperature comparison circuit 90, an indicator light drive circuit 91, an alarm drive circuit 92, and a heater power control circuit. It is connected to the circuit 93 and the like.

The water amount shortage detection circuit 88 includes the water amount detection section 48
The electrodes 48a and 48b and the shield body 48c constituting the microcomputer 77 are connected to an oscillation circuit 94, a switching circuit 95, and a common terminal (not shown) via lead wires, respectively, and the switching circuit 95 is connected to an input port of the microcomputer 77. It is connected to 81.

The power frequency synchronous pulse generation circuit 89 has a base connected to a step-down transformer 96 (output voltage is, for example, AC12V), and a collector connected to
The collector side of the transistor connected to the Vcc power supply is connected to an external interrupt signal input terminal 82 serving as an input port of the microcomputer 77. That is, every time the voltage waveform of the AC power source 97 crosses the zero point, a pulse signal p having the same period and phase as the voltage waveform is generated, and this is input to the microcomputer 77 via the external interrupt signal input terminal 82. is configured to do so.

The temperature comparator circuit 90 compares the detection outputs from the thermistors 46 and 47 with the set value and compares the detection outputs from the thermistors 46 and 47 to
It outputs a signal to the line in response to the temperature detected by 6 and 47. For example, the allowable overheating temperature when the water runs out is 110°C, the boiling operation stop temperature is 97°C, and the temperature when the heating power is turned off is 110°C. 90℃,
A preset value such as 80° C. is input as the automatic boiling start temperature, and a predetermined signal from the temperature comparison circuit 90 is input to the microcomputer 77 via the input port 83.

The indicator light drive circuit 91 activates the boil/warm indicator light 50 or the water shortage/warm indicator light 50 based on the signal output from the output port 86 of the microcomputer 77 in accordance with each operating state such as boiling, warming, water supply alarm, timer operation, etc. The timer operation indicator light 51 is turned on and off.

The alarm drive circuit 92 causes an alarm 98 consisting of a piezoelectric buzzer or the like to emit sound based on signals output from the output port 86 of the microcomputer 77 in accordance with each operating state such as boiling, keeping warm, water supply alarm, timer operation, etc. let

The heater power control circuit 93 connects the collector of a transistor connected via a resistor to the heater control signal output terminal 87 as an output port of the microcomputer 77 to the trigger terminal of the bidirectional switching element via the resistor, and connects the collector of the transistor to the trigger terminal of the bidirectional switching element via the resistor. The switching element is connected to the heater 5 to which AC power 97 is supplied.
It controls the bidirectional switching element on/off based on the heater control signal q from the heater control signal output terminal 87, thereby supplying the current of the AC power supply 97 to the heater 5 for a predetermined period of time. It is configured to flow.

To explain the action based on the electronic control circuit,
When the water runs out, the container 3 is overheated, so when the lower thermistor 47 detects a temperature of 110 degrees Celsius or higher, the pair of indicator lights 50 and 51 both flash.
The alarm 98 emits an alarm to notify of the abnormality, and the power to the heater 5 is turned off.

If the lower thermistor 46 does not exceed 110°C, it is determined whether the timer is operating. That is, when the user turns on the timer set switch 53 to go to bed, for example, the timer set switch 53 is turned on for a predetermined period of time (for example, 6
time) The heater 5 is turned off, and the water shortage and timer operation indicator light 51 lights up. After a predetermined time has elapsed or when the timer set switch 53 is turned off, the heater 5 is immediately turned on.

When the timer is not operating, it is determined whether the amount of water in the container 3 is insufficient. That is, the oscillation circuit 94
For example, when the water level in the container 3 is lower than the water level detection part 48 in a state where 4MHz electrical vibration is constantly emitted, the pair of electrodes 48
As the capacitance between a and 48b becomes smaller, the coupling between the oscillation circuit 94 and the switching circuit 95 becomes looser, so the switching circuit 95 outputs a signal indicating water shortage, and based on this, My 77 issues an alarm command. is output, the alarm 98 sounds, and the water shortage and timer operation indicator light 51 blinks.
At this time, the heater 5 is turned off.

When water is replenished into the container 3 and the water level in the container 3 becomes higher than the water amount detection section 48, the pair of electrodes 48
Since the capacitance between a and 48b increases and the coupling between the oscillation circuit 94 and the switching circuit 95 becomes tighter, the signal indicating water shortage from the switching circuit 95 is stopped, and the alarm command from the microcomputer 77 is stopped. As the water stops, the alarm 98 stops sounding and the water shortage and timer operation indicator light 51 lights up.
will also stop blinking.

When the boiling command switch 52 is turned on, or
When the upper thermistor 46 does not detect a temperature of 97° C. or higher, the boiling and heat retention indicator light 50 flashes to indicate that the boiling operation is in progress, and the heater 5 generates 100% heat to perform the predetermined boiling operation.

A predetermined time (for example, 20 minutes) after energizing this heater 5
When the time has elapsed, both the boiling and heat retention indicator light 50 and the water shortage and timer operation indicator light 51 flash.
The alarm 98 issues an alarm to warn that the boiling operation time has exceeded, and turns off the heater 5.

When it is determined that the water temperature in the container 3 is falling and the lower thermistor 47 detects a temperature lower than 80°C, the heater 5 generates heat of, for example, 5% of the maximum output (30W) and performs a predetermined heat-retaining operation. The boiling and heat retention indicator light 50 lights up to indicate that the heat retention operation is in progress.

(Structure of Bottom Member) As shown in FIGS. 4 to 6, the 81 bottom member 12 is integrally molded from synthetic resin, and the lower edge of the cylindrical case 4 is fitted onto the outer periphery of the upper edge of the annular wall portion 60. A circumferential step 61 is formed to attach to the base plate, and a protruding edge 62 is formed at the lower edge. An inner flange 63 is formed on the inner periphery of the annular wall portion 60 and extends inward from the base of the protruding edge 62 . A housing part 64 is formed in the inner space surrounded by the annular wall part 60, and has a closed upper part and an open lower part.The housing part 64 has a wide storage part 64a and a narrow storage part 64b. It is formed in a continuous convex shape. Rectangular cylindrical attachment portions 65, 65 are defined on both sides of the narrow storage portion 64b of the housing portion 64, and by extending the inner flange 63, the attachment portions 6
5 and 65, and a connecting portion 68 that connects to one side of the wide storage portion 64a. A pair of conductor insertion holes 69 are provided at the corner portions of the side walls of the wide storage portion 64a connected to the connection portion 68, and a pair of conductor insertion holes 69 are provided at the edge of the side wall of the narrow storage portion 64b. It is formed. Furthermore, a positioning protrusion 71 is formed at the opposing portion of the protrusion 62 .

Of the electronic control circuits, at least the microcomputer 77 is connected to the housing section 6.
It is stored in 4. Preferably, together with the microcomputer 77, a water shortage detection circuit 88, a power frequency synchronization pulse generation circuit 89, and a temperature comparison circuit 9 are provided.
0, indicator light drive circuit 91, alarm drive circuit 92,
Heater power control circuit 93 is also housed in housing portion 64 . These circuits 88, 89, 90, 9
1, 92, and 93 are mounted on a printed circuit board 72, and a microcomputer 77 is also mounted on the printed circuit board 72. This printed circuit board 72 is formed in a convex shape corresponding to the housing section 64, and when housed in the housing section 64, screws 74 are inserted into the top wall 64c of the housing section 64 through the screw holes 73 of the printed circuit board 72. It is attached by screwing onto a protruding boss 64d.

When attaching the bottom member 12 to the bottom of the cylindrical case 4, the lower edge of the cylindrical case 4 is fitted onto the circumferential step 61. At this time, a mounting bracket 74 is provided vertically at the bottom of the container 3, and both legs 74a of the bracket 74 are inserted into the mounting portion 65. The leg portion 74a has a curved wing portion 74b, and a tapping hole 74c is formed in the wing portion 74b. By screwing the screw 76 into the tapping hole 74c, the container 3, the cylindrical case 4, and the bottom member 12 are attached and connected. Since the positioning notch 75b formed on the periphery of the bottom cover plate material 75 fits into the protrusion 71 of the bottom member 12, the hole 75a into which the screw 76 is inserted is inserted.
and the tapping hole 74c can be easily positioned. Thus, the bottom opening of the housing portion 64 is closed by the bottom cover plate 75.

As shown in the fifth figure, the bottom member 12 has notches 100 and 101 formed by cutting out the annular wall part 60 located on the front side and the back side, and as shown in the first figure, the bottom member 12 has cutouts 100 and 101 located on the front side and the back side. The lower tongue piece 10a of the decorative member 10 is fitted into the portion 100, and the support 102 of the power connection plug is fitted into the notch 101 on the back side. Furthermore, preferably, a rectangular cylindrical holding portion 10 is provided on the inner circumferential portion of the annular wall portion 60 corresponding to the notch portion 101 on the back side.
3 is integrally molded, and the holding piece 102a of the support body 102 is inserted and held therein.

[Effect of idea]

As a result of the above configuration, the present invention is an electric water heater equipped with a heater power control circuit for controlling the heater and a microcomputer for supplying a heater control signal to the heater power control circuit, and the bottom member is Since the electronic components including the microcomputer are housed in the formed upper closed and lower opened housing part, the microcomputer can be easily assembled into the housing part through the lower opening. Even if a liquid leaks, the leaked liquid will not enter the housing portion whose top is closed, so there is no risk of damaging the microcomputer. Therefore, by repairing a leaking container, an electric water heater can be reused.

In particular, according to the present invention, the bracket 74 protruding from the bottom of the container 3 is inserted into the cylindrical attachment portion 65 of the bottom member 12, and the bottom cover plate 75 superimposed on the lower surface of the bottom member 12 is inserted into the bracket. 74, there is no need to form any screw holes etc. in the housing part 64 housing the electronic components, and the housing part 64 can be completely isolated from the container 3, thereby protecting the electronic components. Becomes excellent.

Further, since the bottom cover plate 75 is screwed to the bracket 74, the bottom member 12 is held between the case 4 and the bottom cover plate 75, so special means for fixing the bottom member 12 itself to the case 4 is required. There is no need to provide the bottom member 12, the bottom member 12 can be firmly and stably attached, and the electronic components can be protected without causing the bottom member 12 to wobble.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional view showing one embodiment of the present invention, Fig. 2 is a longitudinal sectional view showing the pump portion during operation, and Fig. 3 is a longitudinal sectional view showing an embodiment of the present invention.
4 is an exploded perspective view showing the container body, bottom member, printed circuit board, and bottom cover; FIG. 5 is a sectional view taken along the line - - of FIG. 4;
This figure is a sectional view taken along the line -- in FIG. 4, and FIG. 7 is a block diagram showing the control circuit. 1... Container body, 2... Lid body, 3... Container,
4... Case, 5... Boiling heater, 12... Bottom member, 60... Annular wall part, 64... Housing part, 65... Mounting part, 72... Printed circuit board, 7
4...Mounting bracket, 75...Bottom cover plate material.

Claims (1)

[Scope of utility model registration request] A container 3 equipped with a boiling heater 5, a cylindrical case 4 surrounding the outer periphery of the container 3, a bottom member 12 provided at the bottom of the case, a heater power control circuit 93 for controlling the heater, The container 3 includes a microcomputer 77 for supplying a heater control signal to the heater power control circuit, and a bracket 74 protrudes from the bottom of the container 3;
A cylindrical attachment part 65 with upper and lower openings into which the bracket 74 is inserted, and a housing part 64 with a closed upper part and an open lower part are integrally formed, and the electronic parts including the microcomputer are mounted in the housing part 64. By screwing the bottom cover plate 75 superimposed on the lower surface of the bottom member 12 to the bracket 74 via the attachment portion 65, the bottom member 12 is attached to the bottom cover plate 75 and the case 4. An electric water heater characterized in that the lower opening of the housing part 64 is closed by the bottom cover plate material 75.