1. A detection method of an electric water heater is characterized in that a resistance value between an inner container and a heating pipe of the electric water heater is detected, and whether the water level in the inner container is higher than a safe water level or not is judged according to the detected resistance value.

2. The method as claimed in claim 1, wherein the resistance between the inner container and the heating tube is continuously measured for a plurality of times, and if the resistance measured each time is within a predetermined range, the water level in the inner container is determined to be higher than the safe water level.

3. The method as claimed in claim 2, wherein if the resistance between the inner container and the heating pipe exceeds the predetermined range, the water level in the inner container is determined to be lower than the safe water level, and the detection of the resistance between the inner container and the heating pipe is stopped.

4. The method for detecting the electric water heater according to claim 1, wherein after the resistance value between the inner container and the heating pipe is detected, the detected resistance value is converted into an AD value, and if the AD value is smaller than a preset value, the water level in the inner container is judged to be higher than the safe water level.

5. The detection method of the electric water heater according to any one of claims 1 to 4, wherein before the heating pipe starts to heat, the resistance value between the inner container and the heating pipe is detected, and if the water level in the inner container is judged to be higher than the safe water level, the heating pipe is controlled to start to heat the water in the inner container.

6. A detection circuit of an electric water heater using the detection method according to any one of claims 1 to 5, comprising:

the resistance-capacitance circuit is connected with the power supply;

the voltage stabilizing circuit is connected with the resistance-capacitance circuit and the analog-digital converter;

and the protection circuit is connected with the resistance-capacitance circuit.

7. The detection circuit of the electric water heater as claimed in claim 6, wherein the resistance-capacitance circuit comprises an electrical connector J1, pin 1 of the electrical connector J1 is grounded, pin 2 of the electrical connector J1 is connected to a first end of a resistor R11 through a resistor R14, a resistor R13, a resistor R12 and a capacitor C11 which are connected in series in sequence, and a second end of the resistor R11 is connected with a power supply.

8. The detecting circuit of claim 7, wherein the protection circuit comprises a transistor N1, a collector of a transistor N1 is connected to the first end of the resistor R11, a base of a transistor N1 is connected to the pulse input signal PWM, and an emitter of a transistor N1 is grounded.

9. The detection circuit of an electric water heater as claimed in claim 7, wherein the voltage regulator circuit comprises a diode D1, the anode of the diode D1 is connected to the first end of a resistor R11, the cathode of the diode D1 is connected to the first end of a resistor R15, the second end of a resistor R15 is connected to the first end of a resistor R16, the first end of a capacitor C12 and the first end of a resistor R17, the second end of a resistor R17 is connected to the cathode of a voltage regulator tube ZD1, the first end of a capacitor C13 and the analog-to-digital converter, and the second end of the resistor R16, the second end of the capacitor C12, the anode of the voltage regulator tube ZD1 and the second end of the capacitor C13 are all grounded.

10. An electric water heater, comprising:

the heating pipe is arranged in the inner container, and the inner container and the heating pipe are arranged in an insulating way;

the detection circuit board is provided with the detection circuit as claimed in any one of claims 6 to 9, a pin 1 of the electric connector J1 is connected with the inner container, and a pin 2 of the electric connector J1 is connected with the heating tube.

Background

With the improvement of living standard of people, the use demand of hot water is higher and higher, and the water heater is widely applied to daily life of people as a household appliance capable of storing hot water. According to the heating mode of the water heater, the water heater can be divided into an electric water heater, a solar water heater, a gas water heater, a magnetic energy water heater and the like. Among them, the electric water heater becomes the first choice of more and more users due to its advantages such as simple installation, convenient to use.

The electric water heater comprises an inner container used for storing water, and a heating pipe is arranged in the inner container and can heat the water in the inner container. And a temperature sensor is also arranged in the inner container, and when the heating pipe heats water to reach the temperature set by a user, the heating pipe stops working. Because the inner container has the heat preservation function, after the heating pipe stops working, the water in the inner container can be prevented from being rapidly cooled, and a user can use hot water at any time. In the process of heating water by the heating pipe, if the water level in the inner container is low, the dry burning phenomenon can occur, and the service life of the heating pipe is influenced.

An existing Chinese patent discloses an anti-dry heating control method of an electric water heater, which comprises the following steps: acquiring a temperature rise rate threshold; detecting the temperature of an inner container of the electric water heater, and calculating the temperature rise rate according to the temperature of the inner container; judging whether the electric water heater is dry-burned or not according to the temperature rise rate and the temperature rise rate threshold; if the electric water heater is dry-burned, controlling the electric water heater to stop heating; and if the electric water heater is not dry-burned, updating the temperature rise rate threshold according to the temperature rise rate. In the prior art, whether dry burning occurs or not is judged by detecting the temperature rising rate of the inner container in the heating process, if the temperature rising rate exceeds a preset value, the dry burning is judged to occur, and heating is stopped.

Judging whether the water heater is dry-burning in the prior art and needing to be heated for a period of time, judging according to the heating rate of the inner container, if the water heater is dry-burning, the heating pipe is dry-burning for a certain period of time, and the judgment is not timely, so that the service life of the water heater is influenced.

The present invention has been made in view of this situation.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provides a detection method and a detection circuit of an electric water heater and the electric water heater, which can judge whether the water heater is dry or not in time and prolong the service life of the water heater.

In order to solve the technical problems, the invention adopts the technical scheme that:

a detection method of an electric water heater detects the resistance value between an inner container and a heating pipe of the water heater, and judges whether the water level in the inner container is higher than the safe water level or not according to the detected resistance value.

Preferably, the resistance value between the inner container and the heating pipe is continuously detected for multiple times, and if the detected resistance value is within a preset range every time, the water level in the inner container is judged to be higher than the safe water level.

Preferably, if the resistance value between the inner container and the heating pipe is detected to exceed the preset range, the water level in the inner container is judged to be lower than the safe water level, and the detection of the resistance value between the inner container and the heating pipe is stopped.

Preferably, after the resistance value between the inner container and the heating pipe is detected, the detected resistance value is converted into an AD value, and if the AD value is smaller than a preset value, the water level in the inner container is judged to be higher than the safe water level.

Preferably, before the heating pipe starts to heat, the resistance value between the inner container and the heating pipe is detected, and if the water level in the inner container is judged to be higher than the safe water level, the heating pipe is controlled to start to heat the water in the inner container.

Another object of the present invention is to provide a detection circuit of an electric water heater using the detection method, comprising:

the resistance-capacitance circuit is connected with the power supply;

the voltage stabilizing circuit is connected with the resistance-capacitance circuit and the analog-digital converter;

and the protection circuit is connected with the resistance-capacitance circuit.

Preferably, the rc circuit includes an electrical connector J1, pin 1 of the electrical connector J1 is grounded, pin 2 of the electrical connector J1 is connected to a first end of a resistor R11 through a resistor R14, a resistor R13, a resistor R12 and a capacitor C11 which are connected in series in sequence, and a second end of the resistor R11 is connected to a power supply.

Preferably, the protection circuit comprises a transistor N1, a collector of the transistor N1 is connected to a first end of a resistor R11, a base of the transistor N1 is connected to the pulse input signal PWM, and an emitter of the transistor N1 is grounded.

Preferably, the voltage stabilizing circuit comprises a diode D1, the anode of the diode D1 is connected with the first end of a resistor R11, the cathode of the diode D1 is connected with the first end of a resistor R15, the second end of a resistor R15 is connected with the first end of a resistor R16, the first end of a capacitor C12 and the first end of a resistor R17, the second end of a resistor R17 is connected with the cathode of a voltage regulator tube ZD1, the first end of a capacitor C13 and the analog-to-digital converter, and the second end of the resistor R16, the second end of a capacitor C12, the anode of the voltage regulator tube ZD1 and the second end of the capacitor C13 are all grounded.

Another object of the present invention is to provide an electric water heater, comprising:

the heating pipe is arranged in the inner container, and the inner container and the heating pipe are arranged in an insulating way;

the detection circuit board is provided with the detection circuit, the pin 1 of the electric connector J1 is connected with the inner container, and the pin 2 of the electric connector J1 is connected with the heating pipe.

After adopting the technical scheme, compared with the prior art, the invention has the following beneficial effects:

1. the invention judges whether the water level in the electric inner container is higher than the safe water level or not by detecting the resistance value between the inner container and the heating pipe of the electric water heater, the resistance value between the inner container and the heating pipe is larger when the water level in the inner container is lower than the safe water level, and the resistance value between the inner container and the heating pipe is smaller when the water level is higher than the safe water level.

2. According to the invention, the resistance value between the inner container and the heating pipe is continuously detected for multiple times, so that the accuracy of the judgment result is improved, and the detection error caused by accidental factors is avoided.

3. According to the invention, the detection is carried out when the heating pipe stops heating, so that the heating pipe is prevented from being dried and burnt in the detection process, the service life of the heating pipe is prolonged, and the potential safety hazard is reduced.

The following describes embodiments of the present invention in further detail with reference to the accompanying drawings.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention, are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the invention without limiting the invention to the right. It is obvious that the drawings in the following description are only some embodiments, and that for a person skilled in the art, other drawings can be derived from them without inventive effort. In the drawings:

FIG. 1 is a flow chart of a detection method of an electric water heater according to the present invention;

fig. 2 is a schematic diagram of a detection circuit of an electric water heater according to the present invention.

It should be noted that the drawings and the description are not intended to limit the scope of the inventive concept in any way, but to illustrate it by a person skilled in the art with reference to specific embodiments.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and the following embodiments are used for illustrating the present invention and are not intended to limit the scope of the present invention.

In the description of the present invention, it should be noted that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "inner", "outer", etc., indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present invention.

In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; may be directly connected or indirectly connected through an intermediate. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

As shown in fig. 1, an embodiment of the invention introduces a method for detecting an electric water heater, which detects a resistance value between an inner container and a heating pipe of the electric water heater, and determines whether a water level in the inner container is higher than a safe water level according to the detected resistance value.

Generally, a certain amount of water is stored in an inner container of an electric water heater, and a heating pipe is provided in the inner container to heat the water in the inner container. Meanwhile, the inner container has a heat preservation function, the cooling effect of water in the inner container can be reduced, and a user can use hot water stored in the inner container at any time. In order to prolong the service life of the heating pipe and avoid potential safety hazards, the dry burning phenomenon needs to be avoided, wherein the dry burning phenomenon means that the heating pipe is not soaked in water when being heated, the water level in the liner is lower than that of the heating pipe, and the heating pipe is directly contacted with air, so that the heating pipe is easy to age, and the service life of the heating pipe is influenced. When the heating pipe is used for heating, the water level in the inner container needs to be ensured to be higher than a safe water level, and the safe water level means that the water level in the inner container is higher than the heating pipe.

When the water level in the inner container is lower than the safe water level, namely the water level in the inner container is lower than the heating pipe, the inner container and the heating pipe are in an insulation state, and the resistance value between the inner container and the heating pipe is higher. And the water level in the inner bag is higher than safe water level, namely when the water level in the inner bag is higher than the heating pipe, is connected through water between inner bag and the heating pipe, because water has electric conductivity, electrically conducts between inner bag and the heating pipe, and the resistance value between inner bag and the heating pipe is lower.

The invention judges whether the water level in the inner container is higher than the safe water level or not according to the detected resistance value by detecting the resistance value between the inner container and the heating pipe of the electric water heater, and the detection method is simple and easy to realize and has high detection accuracy.

In the embodiment of the invention, the resistance value between the inner container and the heating pipe is continuously detected for multiple times, and if the resistance value detected each time is in the preset range, the water level in the inner container is judged to be higher than the safe water level.

And if the resistance value between the inner container and the heating pipe is detected to exceed the preset range, judging that the water level in the inner container is lower than the safe water level, and stopping detecting the resistance value between the inner container and the heating pipe.

According to the invention, the resistance value between the inner container and the heating pipe is continuously detected for multiple times, so that the accuracy of the judgment result is improved, and the detection error caused by accidental factors is avoided. When the resistance value detected once exceeds the preset range, the heating pipe is dry-burned during heating, the water level in the inner container is considered to be lower than the safe water level, and the detection is stopped.

In the embodiment of the invention, after the resistance value between the inner container and the heating pipe is detected, the detected resistance value is converted into an AD value, and if the AD value is smaller than a preset value, the water level in the inner container is judged to be higher than the safe water level. The preset value is preferably 1.5V.

According to the invention, the detected resistance value is converted into the AD value, so that the stability of the detection result is improved, and the accuracy of the result of judging whether the water level in the inner container is higher than the safe water level is further improved.

In the embodiment of the invention, before the heating pipe starts to heat, the resistance value between the inner container and the heating pipe is detected, and if the water level in the inner container is judged to be higher than the safe water level, the heating pipe is controlled to start to heat the water in the inner container.

When the heating pipe is detected in the heating process, if the water level in the inner container is lower than the safe water level, the heating pipe is still in a dry-burning state in the detection process, and the service life of the heating pipe is influenced.

According to the invention, detection is carried out before the heating pipe starts to heat, and if the water level in the inner container is detected to be higher than the safe water level, the heating pipe is controlled to start to heat water in the inner container; if the water level in the inner container is detected to be lower than the safe water level, the heating pipe is closed, and the heating pipe is prevented from being burnt.

As shown in fig. 2, an embodiment of the present invention introduces a detection circuit of an electric water heater, including: the resistance-capacitance circuit is connected with the power supply; the voltage stabilizing circuit is connected with the resistance-capacitance circuit and the analog-digital converter; and the protection circuit is connected with the resistance-capacitance circuit.

The resistance-capacitance circuit comprises an electric connector J1, a pin 1 of an electric connector J1 is grounded, a pin 2 of an electric connector J1 is connected to a first end of a resistor R11 through a resistor R14, a resistor R13, a resistor R12 and a capacitor C11 which are sequentially connected in series, and a second end of the resistor R11 is connected with a power supply.

The protection circuit comprises a triode N1, the collector of a triode N1 is connected with the first end of a resistor R11, the base of a triode N1 is connected to a pulse input signal PWM, and the emitter of a triode N1 is grounded.

The voltage stabilizing circuit comprises a diode D1, the anode of a diode D1 is connected with the first end of a resistor R11, the cathode of a diode D1 is connected with the first end of a resistor R15, the second end of a resistor R15 is connected with the first end of a resistor R16, the first end of a capacitor C12 and the first end of a resistor R17, the second end of a resistor R17 is connected with the cathode of a voltage regulator tube ZD1, the first end of a capacitor C13 and an analog-to-digital converter, and the second end of a resistor R16, the second end of a capacitor C12, the anode of a voltage regulator tube ZD1 and the second end of a capacitor C13 are all grounded.

When the water level in the inner container is lower than the safe water level, the inner container and the heating pipe are insulated, the resistance between the inner container and the heating pipe is large, when the water level in the inner container is higher than the safe water level, the inner container and the heating pipe are conducted through water, and the resistance between the inner container and the heating pipe is small. According to the invention, the detection circuit is connected with the inner container and the heating pipe, so that the resistance value between the inner container and the heating pipe is detected, and whether the water level in the inner container is higher than the safe water level or not can be judged at any time. Meanwhile, a protection circuit is arranged in the detection circuit, so that elements in the circuit can be prevented from being broken down. And a voltage stabilizing circuit is also arranged, so that the stability of the detection result is improved, and the judgment result of the water level in the inner container is more accurate.

An embodiment of the present invention introduces an electric water heater, including: the heating pipe is arranged in the inner container, and the inner container and the heating pipe are arranged in an insulating way; the detection circuit board is provided with the detection circuit, the pin 1 of the electric connector J1 is connected with the inner container, and the pin 2 of the electric connector J1 is connected with the heating pipe.

Generally, a certain amount of water is stored in an inner container of an electric water heater, and a heating pipe is provided in the inner container to heat the water in the inner container. Meanwhile, the inner container has a heat preservation function, the cooling effect of water in the inner container can be reduced, and a user can use hot water stored in the inner container at any time. In order to prolong the service life of the heating pipe and avoid potential safety hazards, the dry burning phenomenon needs to be avoided, wherein the dry burning phenomenon means that the heating pipe is not soaked in water during heating and is directly contacted with air, so that the heating pipe is easy to age. When the heating pipe is used for heating, the water level in the inner container needs to be ensured to be higher than a safe water level, and the safe water level means that the water level in the inner container is higher than the heating pipe.

When the water level in the inner container is lower than the safe water level, namely the water level in the inner container is lower than the heating pipe, the inner container and the heating pipe are in an insulation state, and the resistance value between the inner container and the heating pipe is higher. And the water level in the inner bag is higher than safe water level, namely when the water level in the inner bag is higher than the heating pipe, is connected through water between inner bag and the heating pipe, because water has electric conductivity, electrically conducts between inner bag and the heating pipe, and the resistance value between inner bag and the heating pipe is lower.

The invention detects the resistance value between the inner container and the heating pipe through the detection circuit, and judges whether the water level in the inner container is higher than the safe water level according to the detection result of the resistance value, the detection method is simple and easy to realize, and the detection accuracy is high.

In the embodiment of the invention, the inner container is provided with the mounting hole, the heating pipe penetrates through the mounting hole and extends into the inner container, and the heating pipe is connected with the flange plate fixed on the outer side of the inner container. The inner container is provided with a bolt protruding towards the outer side of the inner container, the flange plate is provided with a screw hole, the bolt penetrates through the screw hole, and the flange plate is fixed on the outer side of the inner container by screwing the bolt on the nut.

Be equipped with first insulating part between inner bag and ring flange, be equipped with second insulating part on the bolt, second insulating part cover is outside the bolt, and second insulating part sets up between ring flange and bolt. One side of the second insulating part, which is close to the nut, is provided with an annular flange, and the annular flange is clamped between the nut and the flange plate.

A first electrode is provided between the flange and the annular flange and connected by a wire to pin 2 of the electrical connector J1, and a second electrode is provided between the annular flange and the nut and connected by a wire to pin 1 of the electrical connector J1. The first electrode is connected to the heating pipe through a flange plate, and the second electrode is connected to the inner container through a bolt.

When the water level in the inner container is lower than the safe water level, the water level in the inner container is lower than the heating pipe, and the flange plate and the inner container are insulated due to the fact that the first insulating part is arranged between the flange plate and the inner container, which shows that the first electrode and the second electrode are insulated. And when the water level in the inner container is higher than the safe water level, the water level in the inner container is higher than the heating pipe, the heating pipe and the inner container are conducted through water, and the first electrode and the second electrode are conducted.

The invention detects the resistance value between the inner container and the heating pipe through the detection circuit, and judges whether the water level in the inner container is higher than the safe water level according to the detection result of the resistance value, the detection method is simple and easy to realize, and the detection accuracy is high.

In the description provided herein, numerous specific details are set forth. It is understood, however, that embodiments of the invention may be practiced without these specific details. In some instances, well-known methods, structures and techniques have not been shown in detail in order not to obscure an understanding of this description.

All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and all of the processes or elements of any method or apparatus so disclosed, may be combined in any combination, except combinations where at least some of such features and/or processes or elements are mutually exclusive. Each feature disclosed in this specification (including any accompanying claims, abstract and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise.

Furthermore, those skilled in the art will appreciate that while some embodiments described herein include some features included in other embodiments, rather than other features, combinations of features of different embodiments are meant to be within the scope of the invention and form different embodiments.

The above embodiments are only preferred embodiments of the present invention, and not intended to limit the present invention in any way, and although the present invention has been disclosed by the preferred embodiments, it is not intended to limit the present invention, and those skilled in the art can make various changes and modifications to the equivalent embodiments by using the technical contents disclosed above without departing from the technical scope of the present invention, and the embodiments in the above embodiments can be further combined or replaced, but any simple modification, equivalent change and modification made to the above embodiments according to the technical spirit of the present invention still fall within the technical scope of the present invention.