KR101314938B1 - Method for heating water and water heating apparatus to be applied - Google Patents

Abstract

PURPOSE: A method for heating water and a hot water heater using the same are provided to separate power sources into an insulation group and a non-insulation group to be used for the operation of a sensor and the generation of heat and to control the operation of the hot water heater by sensing water levels inside a water tank. CONSTITUTION: A hot water heater (200) comprises a power unit (210), a pulse generating unit (240), a heating unit (270), a signal transformer (220), a water level sensor (250), and a control unit (260). A frequency is determined to be proportional to a frequency of alternating current power based on the alternating current power in the pulse generating unit generating a round pulse in which the phase is periodically inverted. The heating unit heats the liquid in a water tank by using the round pulse. The signal transformer induces an alternating current power signal insulated with the alternating current power from the round pulse. The control unit stops the operation of the heating unit according to sensed water levels. [Reference numerals] (210) Power unit; (220) Signal transformer; (230) Rectification unit; (240) Pulse generating unit; (250) Water level sensor; (260) Control unit; (270) Heating unit

Description

Hot water heating method and hot water heater to which the method is applied {METHOD FOR HEATING WATER AND WATER HEATING APPARATUS TO BE APPLIED}

The present invention relates to an industrial hot water heater, and more specifically, to separate a power supply into an insulator and a non-insulator, while maintaining a high-efficiency heat generated using the power of the non-insulator, while detecting the liquid level using the power of the insulator To a hot water heater.

Techniques that constitute the background of the present invention are disclosed in the following documents.
1) Publication No.: 2006-0000633 (January 06, 2006), "Water level detection device"
2) Publication No. 2009-0019530 (2009.02.25), "boiler circulation pump driving device and method thereof"
Hot water heaters (especially 'pigtail heaters') are electric appliances that heat liquids such as water using general commercial AC power. The hot water heater has a simple structure and is easy to carry, so it is widely used for heating water using general commercial AC power in places where boiler facilities are not available and where hot water cannot be used (building works, factories, farms, military units, etc.). It is used.

The hot water heater is installed on one side of the tank by using the latch, and once used, it is used for a long time. That is, the installed hot water heater operates continuously for a long time, and the warmed water may evaporate according to the operation of the hot water heater. If most of the water in the tank evaporates, the heat generating portion of the hot water heater may overheat and cause a fire.

Therefore, it is urgent to develop a technology that can stop the operation of the hot water heater by detecting the water level in the water tank while maintaining the advantage of simply installing the hot water.

An object of the present invention is to provide a hot water heater that separates the power supply into an insulator and a non-insulator and uses each of them for operation and heat generation of the sensor.

An object of the present invention is to detect the water level in the water tank to control the operation of the hot water heater.

According to an aspect of an exemplary embodiment, a power supply unit for receiving AC power, a pulse generator for generating a rectangular pulse whose frequency is determined in proportion to the frequency of the AC power based on the AC power, the phase is periodically inverted, the A heat generating unit for heating the liquid in the tank using a rectangular pulse, a signal transformer for inducing an AC signal insulated from the AC power from the rectangular pulse, a water level sensor for detecting the level of the liquid using the insulated AC signal, There is provided a hot water heater including a control unit for stopping the operation of the heating unit according to the detected water level.

The rectifier may further include a rectifier configured to generate a pulse wave by full-wave rectifying the AC power, wherein the pulse generator may generate the rectangular pulse based on the pulse wave.

The pulse generator may include a zener diode having a predetermined breakdown voltage and a voltage of the first transistor passing the pulse wave and the pulse wave passing through the first transistor when the voltage of the pulse wave is lower than the breakdown voltage. And a capacitor charged with the capacitor, wherein the voltage charged in the capacitor is discharged when the voltage of the pulse wave is higher than the breakdown voltage, and the discharged voltage may form the square pulse.

In addition, when the voltage of the pulse wave is higher than the breakdown voltage, it may further include a second transistor for passing the pulse wave.

Here, the water level sensor is drawn out of the two strands from the signal transformer and inserted into the liquid to pass the AC signal through the liquid, when the voltage of the AC signal is greater than '0', passing through the AC signal A first diode may be further included.

When the voltage of the AC signal is less than '0', the AC signal may further include a second diode passing through the AC signal and connected in parallel with the first diode.

Here, the controller may control the operation of the heating unit in consideration of the temperature of the liquid.

According to another exemplary embodiment, the step of receiving AC power, generating a rectangular pulse whose frequency is determined in proportion to the frequency of the AC power based on the AC power, the phase is periodically inverted, the rectangular Heating the liquid in the tank using pulses, inducing an AC signal insulated from the spherical pulses with the AC power, sensing the level of the liquid using the insulated AC signal, and the sensed water level In accordance with the present invention there is provided a hot water heating method comprising the step of stopping the heating operation.

Here, the method may further include generating a pulse wave by full-wave rectifying the AC power, and generating the pulse may generate the square pulse based on the pulse wave.

The generating of the pulse may include comparing the voltage of the pulse wave with a predetermined breakdown voltage, and passing the pulse wave in the case where the voltage of the pulse wave is lower than the breakdown voltage. And charging the capacitor for charging the voltage of the pulse wave, wherein the voltage charged in the capacitor is discharged when the voltage of the pulse wave is higher than the breakdown voltage, and the discharged voltage forms the square pulse. Can be.

The detecting of the water level may include passing the alternating current signal to the liquid using an electrode drawn in two strands from the signal transformer, and the alternating current signal when the voltage of the alternating signal is less than '0'. The method may further include bypassing through the first diode.

The method may further include passing the AC signal through a second diode connected in parallel with the first diode when the voltage of the AC signal is greater than '0'.

And, the stopping step may stop the heating operation in consideration of the temperature of the liquid.

According to the present invention, the power source can be separated into an insulator and a non-insulator, and each can be used for the operation and heat generation of the sensor.

According to the present invention, it is possible to control the operation of the hot water heater by detecting the water level in the water tank.

1 is a view schematically showing the structure of a hot water heater.
Fig. 2 is a block diagram showing the structure of a hot water heater according to an exemplary embodiment.
3 is a block diagram illustrating a structure of a pulse generator according to an exemplary embodiment.
4 is a diagram illustrating a pulse generated according to a pulse generator according to an exemplary embodiment.
5 is a diagram illustrating a structure of a water level sensor according to an exemplary embodiment.
6 is a flowchart illustrating step by step a method of heating hot water according to an exemplary embodiment.
7 is a flowchart illustrating a step-by-step method of generating a pulse according to an exemplary embodiment.
8 is a flowchart illustrating step by step a method for detecting a water level according to an exemplary embodiment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a view schematically showing the structure of a hot water heater.

The hot water heater 100 may include a body 150, a heat generating unit 160, a temperature control knob 110, an indicator lamp 120, a power switch 130, a latch 140, and a temperature sensor 170. have. According to one side, the lower end 180 of the heat generating unit 160 may be rolled up in a pigtail shape to maximize the connection surface with the liquid.

The hot water heater 100 is fixed to one side of the water tank using the clasp 140.

The user may operate the power switch 130 to supply power to the hot water heater 100. The heat generating unit 160 connected to the body 150 generates heat at a high temperature by using the supplied power. The temperature of the heat generating unit 160 may be controlled using the temperature adjusting knob 110.

The temperature sensor 170 is inserted into the liquid contained in the tank to detect the temperature of the liquid.

When power is supplied to the hot water heater 100 or the temperature of the liquid in the water tank rises abnormally, the hot water heater 100 may report this to the user using the display lamp 120.

Fig. 2 is a block diagram showing the structure of a hot water heater according to an exemplary embodiment.

The hot water heater 200 includes a power supply 210, a signal transformer 220, a rectifier 230, a pulse generator 240, a water level sensor 250, a controller 260, and a heat generator 270.

The power supply unit 210 receives AC power. According to one side, the AC power received by the power supply unit 210 is a commercial power supply to a general home, factory, farm, etc., may be 220V, 60Hz AC power.

The signal transformer 220 induces an AC signal insulated from the AC power from the rectangular pulse generated by the pulse generator 240. The induced alternating current signal is supplied to the water level sensor 250.

The rectifier 230 rectifies the AC power received by the power supply 210. According to one side, the rectifying unit 230 may rectify the AC power using a full-wave rectification technique.

The pulse generator 240 generates a rectangular pulse whose frequency is determined in proportion to the frequency of the AC power based on the AC power, and whose phase is periodically inverted. According to one side, the frequency of the square pulse may be twice the frequency of the AC power.

Hereinafter, detailed operations of the rectifier 230 and the pulse generator 240 will be described in detail with reference to FIGS. 3 to 4.

The heat generating unit 270 heats the liquid in the tank using a rectangular pulse based on the pulse wave generated by the rectifying unit 230. According to one side, the heat generating unit 270 may be in the form of a heating wire, that is, a nichrome wire in the form of a coil in the metal rod.

On the other hand, the water level sensor 250 detects the level of the liquid in the tank using the isolated AC signal. If the hot water heater 200 is used for a long time without any control, the heated liquid may evaporate and the level of the liquid in the water tank may be lowered by more than a certain limit. If the heat generating part 270 of the hot water heater 200 is exposed out of the liquid, the heat generating part 270 is overheated to increase the risk of fire. Therefore, sensing the level of liquid in the bath is essential for the safe use of the hot water heater.

The level sensor 250 detects the level of the liquid and reports it to the controller 260.

The controller 260 stops the operation of the heat generator 270 according to the detected water level. According to one side, the control unit 260 may stop the operation of the heating unit 270 when it is determined that the heating unit 270 is exposed to the outside of the liquid.

According to one side, the water level sensor 250 includes an electrode, and when the position of the electrode is lower than the liquid level, it may periodically transmit a control signal to the control unit 260. If the control unit 260 does not receive the control signal periodically, it may be determined that the water level sensor 250 is exposed to the outside of the liquid, and the heat generating unit 270 may also be determined to be exposed to the outside of the liquid.

3 is a block diagram illustrating a structure of a pulse generator according to an exemplary embodiment.

The pulse generator includes a plurality of resistors 310, 312, and 321, a zener diode 311, a rectifying diode 331, transistors 322 and 332, and a capacitor 333.

4 is a diagram illustrating a pulse generated according to a pulse generator according to an exemplary embodiment. Hereinafter, an operation of the pulse generator will be described with reference to the pulse illustrated in FIG. 4.

The AC power received by the power supply unit 210 may have the form of a sine wave as shown in the first 410 of FIG. 4.

According to one side, the rectifier 230 may full-wave rectified AC power. In this case, the full-wave rectified AC power may have the form of a pulse wave as shown in the second 420 of FIG. 4. The pulse wave 420 is rectified by the rectifying diode 331. The rectified pulse wave wave 420 is supplied to the heating unit 270 through a rectangular pulse process to be described later.

The zener diode 311 is also called a constant voltage diode and is a diode that maintains a constant voltage using a zener effect. This constant voltage is referred to as the breakdown voltage 430 set for the zener diode 311.

When the voltage of the rectified pulse wave wave 420 is higher than the breakdown voltage 430 of the zener diode 311, the current passes through the zener diode 311. The current passing through the zener diode 311 passes through the second transistor 322. The current passing through the second transistor 322 draws down the current passing through the third resistor 321 to close the first transistor 332.

When the voltage of the rectified pulse wave wave 420 is lower than the breakdown voltage 430 of the zener diode 311, the current operates the first transistor 332 via the third resistor 310. The voltage until the first transistor 332 is operated is charged to the capacitor 334 via the rectifying diode 331.

That is, among the rectified pulse wave waves 420, only the portion 440 whose voltage is lower than the breakdown voltage 430 of the zener diode 311 is used to charge the capacitor 334. If the voltage of the rectified pulse wave wave 420 is higher than the breakdown voltage 430, the charge charged in the capacitor 334 is discharged.

The process is repeated every cycle of the input voltage sine wave. During the process in which the first transistor 332 is operated and the closing is repeated, the charges charged in the capacitor 334 are discharged during the time when the first transistor 332 is closed, and the time when the first transistor 332 is operated. During the charge, the capacitor 334 is charged. Charges discharged from the capacitor 334 form a spherical pulse 450.

The rectangular pulse 450 has a value other than '0' while the first transistor 332 is in operation, and has a value of '0' during the time when the first transistor 332 is not in operation. In addition, the phase of the pulse wave 420 has a phase of '+' in the time period when the voltage is low, and the phase of the pulse wave 420 has a phase of '-' and the phase is inverted periodically. The frequency of the rectangular pulse 450 is determined in proportion to the frequency of the AC power received by the power supply unit 210. According to one side, the frequency of the rectangular pulse 450 may be determined to be twice the frequency of the AC power.

5 is a diagram illustrating a structure of a water level sensor according to an exemplary embodiment.

The water level sensor includes a plurality of electrodes 531 and 532, a capacitor 520, and diodes 540 and 551 connected in parallel to each other and in different directions.

The signal transformer 510 receives a rectangular pulse 450 generated by the pulse generator 240 on the primary side. In this case, on the secondary side of the signal transformer 510, an AC signal in a pulse form insulated from AC power is induced.

The plurality of electrodes 531, 532 of the water level sensor are inserted into the liquid in the water tank. If the level of the liquid in the bath is higher than the position of the electrodes 531, 532, the alternating signal may be conducted to the other electrode 532 via the liquid in the bath via the electrode 531.

If the power applied to the electrodes 531 and 532 to measure the water level is direct current (DC), the electrode is electrolyzed by the oxidation-reduction reaction and the surface of the electrode is corroded. However, in the present invention, an AC signal is applied to the electrodes 531 and 532 to measure the water level. Therefore, the oxidation reaction and the reduction reaction are periodically repeated alternately. Accordingly, the water level can be measured semi-permanently without corrosion of the electrodes 531 and 532.

When the voltage of the AC signal passing through the liquid is '-', the AC signal may be bypassed using the first diode 540 among the plurality of diodes. In addition, when the voltage of the alternating current signal passing through the liquid is '+', the alternating current signal may pass through the second diode 551 among the plurality of diodes. The second diode 551 is connected in parallel with the first diode 540 and is opposite in direction.

According to one side, the second diode 551 may be part of the photo coupler 550. The photo coupler 550 optically combines a light emitting element and a light receiving element for the purpose of transmitting an electrical signal in a state in which the circuits are electrically insulated from each other. The current passing through the second diode 551 drives the light emitting element included in the photo coupler 550, and the light receiving element 552 is driven by the light generated by the light emitting element to transmit a control signal to the controller 260. do.

If the level of the liquid in the bath is lower than the position of the electrodes 531, 532, the AC signal cannot pass through the liquid, and thus the photo coupler 550 cannot operate. Therefore, the light receiving element 552 may not transmit a control signal to the controller 260.

2 to 5, the water level sensor 250 of the hot water heater 200 uses the AC signal completely insulated from the AC power received by the power supply unit 210 to adjust the level of the liquid in the tank. Detect. In addition, the heat generating unit 270 of the hot water heater 220 may heat the liquid using a direct current that is not insulated from the AC power. DC current that is not insulated with AC power supply can secure high voltage and current, and can heat liquid efficiently.

In general, a switching power supply is used to obtain a power supply that is isolated from an AC power supply. However, switching power supplies are very expensive and generate heat, requiring complex structures for cooling. In addition, additional circuitry is required to use non-isolated power supplies.

2 to 5, the hot water heater 200 may use both an insulated power source and a non-insulated power source using a circuit having a simple structure. The isolated power supply may drive the water level sensor operating at a low operating voltage, and the non-isolated power supply may drive the heat generating unit 270 operating at a high operating voltage. Therefore, the size of the hot water heater is reduced, there is no heat generation can configure the hot water heater 200 of a simple structure.

6 is a flowchart illustrating step by step a method of heating hot water according to an exemplary embodiment.

In step 610, the hot water heater receives AC power. According to one side, the AC power received by the hot water heater may be AC power of 220V, 60Hz as a commercial power source.

In step 620, the hot water heater rectifies the AC power. According to one side, the hot water heater may convert the AC power into a pulse wave using a full wave rectification technique, and rectify the pulse wave using a rectifier diode.

In step 630, the hot water heater generates a spherical pulse from the pulse wave. A configuration in which the hot water heater generates a rectangular pulse from the pulse wave will be described in detail with reference to FIG. 7.

In step 640, the hot water heater uses the spherical pulses to heat the liquid in the water bath. According to one side, the spherical pulse may be supplied to the heating unit included in the hot water heater. The heat generating unit may have a shape in which a heating wire, that is, a nichrome wire in the form of a coil is included in the metal rod.

In step 650, the hot water heater derives an alternating signal from the spherical pulses. An AC signal is a signal that is electrically insulated from AC power. The induced alternating signal is supplied to the level sensor.

In step 660, the hot water heater detects the level of the liquid in the tank using the AC signal. A configuration of detecting the level of the liquid in the tank using the AC signal will be described in detail with reference to FIG. 8.

In step 670, the hot water heater may stop the operation of heating the liquid in accordance with the sensed water level. For example, the hot water heater may determine that the water level in the water tank is low when it does not receive a control signal from the water level sensor or periodically. In this case, the hot water heater may interrupt the operation of heating the liquid by cutting off the power supply to the heat generating unit.

According to one side, the hot water heater may further include a temperature sensor. In this case, in step 670, the hot water heater may stop the heating operation in consideration of the temperature of the liquid. The hot water heater may receive information about the temperature of the liquid in the tank or the temperature in the tank from the temperature sensor, and stop the heating operation when the received temperature is higher than the threshold.

7 is a flowchart illustrating a step-by-step method of generating a pulse according to an exemplary embodiment.

In step 710, the hot water heater compares the voltage of the pulse wave with a predetermined threshold voltage. Here, the breakdown voltage of the zener diode may be used as the threshold voltage.

If the voltage of the pulse wave is lower than the threshold voltage, the hot water heater passes the pulse wave through the first transistor in step 720. The pulse wave passing through the first transistor is charged to the capacitor in step 730.

If the voltage of the pulse wave is higher than the threshold voltage, the hot water heater passes the pulse wave through the second transistor in step 740. In this case, the pulse wave passing through the second transistor is not supplied to the capacitor. Thus, the electric charge charged in the capacitor is discharged.

Step 720, step 730, step 740, and step 750 are repeated according to the voltage of the pulse wave. That is, the charge charged in the capacitor in step 730 is discharged in step 750. Charges discharged from the capacitor form a square pulse.

The rectangular pulse has a value other than '0' while the first transistor is in operation, and has a value '0' during the time when the first transistor is not in operation. In addition, the phase of the pulse wave has a phase of '+' in the time period when the voltage is low, and the phase of the pulse wave has a phase of '-' and the phase is periodically reversed. The frequency of the square pulse is determined in proportion to the frequency of the AC power received by the hot water heater. Depending on one side, the frequency of the square pulse can be determined to be twice the frequency of the AC power.

8 is a flowchart illustrating step by step a method for detecting a water level according to an exemplary embodiment.

In step 810, the hot water heater passes an alternating current signal through the liquid. According to one side, the hot water heater may induce an AC signal from the AC power using a signal transformer. In this case, the hot water heater may draw two strands of the electrode from the signal transformer. According to one side, the electrode drawn from the signal transformer may be inserted into the liquid in the water bath to pass the AC signal.

In step 820, the hot water heater determines whether the voltage of the AC signal is greater than '0'.

If the voltage of the AC signal is greater than '0', the hot water heater may pass the AC signal through the first diode in step 830.

If the voltage of the AC signal is less than '0', the hot water heater may pass the AC signal through the second diode in step 830. Here, the second diode is connected in parallel with the first diode, the connection direction is a diode in the opposite direction.

According to one side, the second diode may be part of the photo coupler. The current passing through the second diode drives the light emitting device included in the photocoupler, and the light receiving device is driven by the light generated by the light emitting device to transmit a control signal. Since the AC signal is in the form of a sine wave, the voltage of the AC signal changes with time. Therefore, in operation 840, the light receiving element may periodically transmit a control signal.

If the level of liquid in the bath is lower than the position of the electrode, then in step 810 the alternating signal cannot pass through the liquid. Therefore, the photo coupler cannot operate and the light receiving element cannot transmit the control signal.

According to the embodiment shown in Figure 8, the hot water heater detects the level of the liquid in the tank using an alternating current signal whose phase is periodically changed. If the power applied to the electrode to measure the water level is direct current (DC), the electrode is electrolyzed by the oxidation-reduction reaction and the surface of the electrode is corroded. However, in the present invention, an AC signal is applied to the electrode in order to measure the water level. Therefore, the oxidation reaction and the reduction reaction are periodically repeated alternately. Therefore, the water level can be measured semi-permanently without corrosion of the electrode.

6 to 8, the hot water heater senses the water level using an AC signal insulated from the AC power. In addition, the hot water heater may heat the liquid by using a direct current that is not insulated from the alternating current power. Non-isolated DC current can ensure a high voltage and current can efficiently heat the liquid. In addition, the hot water heater can effectively operate a sensitive sensor operating at a low voltage by using the isolated AC signal.

6 to 8 may use both an insulated power supply and a non-isolated power supply with only a simple circuit structure. Therefore, the structure of the hot water heater is simplified and the heat generation is less, so that a safe hot water heater can be used.

The methods according to embodiments of the present invention may be implemented in the form of program instructions that can be executed through various computer means and recorded in a computer-readable medium. The computer readable medium may include program instructions, data files, data structures, etc. alone or in combination. The program instructions recorded on the medium may be those specially designed and constructed for the present invention or may be available to those skilled in the art of computer software.

As described above, the present invention has been described by way of limited embodiments and drawings, but the present invention is not limited to the above embodiments, and those skilled in the art to which the present invention pertains various modifications and variations from such descriptions. This is possible.

Therefore, the scope of the present invention should not be limited to the described embodiments, but should be determined by the equivalents of the claims, as well as the claims.

200: hot water heater
210:
220: signal transformer
230: rectifier
240: pulse generator
250: water level sensor
260:
270: heating portion

Claims (14)

A power supply unit for receiving AC power;
A pulse generator configured to generate a rectangular pulse whose frequency is determined in proportion to the frequency of the AC power based on the AC power and whose phase is periodically inverted;
A heating unit for heating the liquid in the water tank using the spherical pulses;
A signal transformer for inducing an AC signal insulated from the AC power from the rectangular pulse;
A level sensor for sensing the level of the liquid using the insulated AC signal; And
Control unit to stop the operation of the heating unit in accordance with the detected water level
Hot water heater comprising a. The method of claim 1,
Rectifier for full-wave rectifying the AC power to generate a pulse wave
Further comprising:
The pulse generator generates the rectangular pulse based on the pulse wave.
Hot water heater. 3. The method of claim 2,
The pulse generator,
A zener diode with set breakdown voltage;
A first transistor configured to pass the pulse wave when the voltage of the pulse wave is lower than the breakdown voltage; And
A capacitor for charging the voltage of the pulse wave passing through the first transistor
Lt; / RTI >
The voltage charged in the capacitor is discharged when the voltage of the pulse wave is higher than the breakdown voltage,
The discharged voltage forms the rectangular pulse.
Hot water heater. The method of claim 3,
The pulse generator,
A second transistor for passing the pulse wave when the voltage of the pulse wave is higher than the breakdown voltage
Hot water heater comprising more. The method of claim 1,
The water level sensor comprises:
An electrode drawn out of the signal transformer into two strands and inserted into the liquid to pass the alternating current signal through the liquid; And
A first diode passing the alternating current signal when the voltage of the alternating current signal is greater than '0'
Hot water heater comprising a. The method of claim 5,
The water level sensor comprises:
When the voltage of the AC signal is less than '0', the second diode passing through the AC signal and connected in parallel with the first diode
Hot water heater comprising more. The method of claim 1,
The control unit,
Controlling the operation of the heating unit in consideration of the temperature of the liquid
Hot water heater. Receiving AC power;
Generating a rectangular pulse whose frequency is determined in proportion to the frequency of the AC power and whose phase is periodically inverted based on the AC power;
Heating the liquid in the water tank using the spherical pulses;
Deriving an AC signal isolated from the AC power from the rectangular pulse;
Sensing the level of the liquid using the insulated alternating current signal; And
Stopping the heating operation according to the sensed water level
Hot water heating method comprising a. 9. The method of claim 8,
Generating a pulse wave by full-wave rectifying the AC power
Further comprising:
Generating the pulse,
Generating the square pulse based on the pulse wave
Hot water heating method comprising a. 10. The method of claim 9,
Generating the pulse,
Comparing the voltage of the pulse wave with a breakdown voltage;
Passing the pulse wave when the voltage of the pulse wave is lower than the breakdown voltage; And
Charging the voltage of the passed pulse wave into a capacitor
Further comprising:
The voltage charged in the capacitor is discharged when the voltage of the pulse wave is higher than the breakdown voltage,
The discharged voltage forms the rectangular pulse.
Hot water heating method. 9. The method of claim 8,
Detecting the water level,
Passing the alternating signal through the liquid using an electrode drawn in two strands from a signal transformer; And
Bypassing the AC signal through the first diode when the voltage of the AC signal is smaller than '0'.
Hot water heating method comprising a. 12. The method of claim 11,
Detecting the water level,
Passing the alternating current signal through a second diode connected in parallel with the diode when the voltage of the alternating current signal is greater than '0';
Hot water heating method comprising more. 9. The method of claim 8,
The stopping step is,
Stopping the heating operation in consideration of the temperature of the liquid
Hot water heating method comprising a. A computer-readable recording medium having recorded thereon a program for executing the method of any one of claims 8 to 13.

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