A water leakage detection circuit

Abstract

The present invention provides a water leakage detection circuit, which includes: a first detection switch, a drive switch, a controllable switch and a second detection switch, wherein one end of the first detection switch is connected to a neutral line; the first control end of the drive switch is connected to the other end of the first detection switch, the second control end is connected to a live line, the first output end of the second detection switch is connected to the detection signal input end of an external controller, and the second output end is connected to the second output end of the second detection switch and is connected to an external level signal; one end of the second detection switch is grounded, and the other end is connected to the control end of the controllable switch. By implementing the present invention, the first detection switch and the second detection switch are used to jointly detect the water leakage of the dishwasher, and whether water leakage occurs is determined by two detection methods, thereby improving the reliability and detection efficiency of the entire water leakage detection circuit detection, and avoiding the problem that overflow detection cannot be performed when the single float detection fails.

Description

Technical Field

[0001] The invention relates to the technical field of household appliances, and in particular to a water leakage detection circuit. Background Art

[0002] With the advancement of science and technology and the improvement of people's living standards, dishwashers are increasingly used in daily life. Since dishwashers are water-related electrical appliances, there are many problems with the connection of hoses of different specifications in the entire dishwasher. As the dishwasher is used for a longer time, the interface hoses of some devices will age. When some water leaks out, the leaked water drips into the bottom cover and flows into the overflow tank. In order to promptly detect the hidden dangers of dishwasher leakage and avoid unnecessary economic losses to users, dishwashers generally add overflow detection devices to the overflow tank of the base. The detection device is generally a float switch. When water leaks to the bottom cover, a certain amount of water will gather in the low-lying part of the bottom cover. The buoyancy of the water will float the foam float, and the convex part of the float will push against the micro switch above the float. The switch will operate and output a water leakage signal, thereby realizing the water leakage detection function. However, when the float switch fails, the water leakage cannot be detected in time, affecting the reliability of the entire detection device. Summary of the invention

[0003] In view of this, an embodiment of the present invention provides a water leakage detection circuit to overcome the problem of low reliability of water leakage detection devices in the prior art.

[0004] An embodiment of the present invention provides a water leakage detection circuit, including: a first detection switch, a drive switch, a controllable switch and a second detection switch, wherein one end of the first detection switch is connected to a neutral line; a first control end of the drive switch is connected to the other end of the first detection switch, and the second control end is connected to a live line; a first output end and a first output end of the second detection switch are connected to a detection signal input end of an external controller, and a second output end and a second output end of the second detection switch are connected to an external level signal; one end of the second detection switch is grounded, and the other end is connected to the control end of the controllable switch.

[0005] Optionally, the first detection switch is a float switch, and the water leakage detection circuit further includes: a float arranged corresponding to the float switch and installed at a preset water leakage detection position.

[0006] Optionally, the second detection switch is two probes installed at preset water leakage detection positions.

[0007] Optionally, the probe is a metal probe.

[0008] Optionally, the drive switch is a photocoupler.

[0009] Optionally, the controllable switch is a triode.

[0010] Optionally, the water leakage detection circuit also includes: a rectifier diode and a first resistor, wherein the forward end of the rectifier diode is connected to the live wire, and the reverse end is connected to the second control end of the drive switch; one end of the first resistor is connected to the other end of the first detection switch, and the other end is connected to the second control end of the drive switch.

[0011] Optionally, the water leakage detection circuit further includes: an alarm device, which is connected to the output end of the external controller, and when the detection signal input end of the external controller receives a water overflow signal, an alarm control signal is generated to drive the alarm device to alarm.

[0012] Optionally, when the external level signal is at a high level, the water leakage detection circuit also includes: a second resistor, a third resistor and one or more filter capacitors connected in parallel, wherein one end of the second resistor is connected to the first output end of the driving switch, and the other end is respectively connected to one end of the third resistor, the detection signal input end of the external controller and one end of the one or more filter capacitors connected in parallel, the other end of the third resistor is grounded, and the other end of the one or more filter capacitors connected in parallel is grounded.

[0013] Optionally, when the external level signal is at a low level, the water leakage detection circuit also includes: a DC power supply, a fourth resistor, a fifth resistor, a sixth resistor and one or more filter capacitors connected in parallel, wherein the DC power supply is connected to one end of the fifth resistor and one end of the sixth resistor respectively through the fourth resistor, the other end of the fifth resistor is connected to the first output end of the drive switch, the other end of the sixth resistor is connected to the detection signal input end of the external controller and one end of the one or more filter capacitors connected in parallel, and the other end of the one or more filter capacitors connected in parallel is grounded.

[0014] The technical solution of the present invention has the following advantages:

[0015] The water leakage detection circuit provided in the embodiment of the present invention detects the water leakage of the dishwasher through the first detection switch and the second detection switch, and determines whether water leakage occurs through two detection methods, thereby improving the detection reliability and detection efficiency of the entire water leakage detection circuit, and avoiding the problem of being unable to perform overflow detection due to failure of a single float detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0017] Figure 1 Schematic diagram of the structure of a water leakage detection circuit according to an embodiment of the present invention;

[0018] Figure 2 FIG. 4 is another structural schematic diagram of a water leakage detection circuit according to an embodiment of the present invention. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0020] The technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0021] Figure 1 FIG. 4 shows a schematic diagram of a water leakage detection circuit according to an embodiment of the present invention. Figure 1 As shown, the water leakage detection circuit includes: a first detection switch SWCH1, a drive switch U1, a controllable switch Q1 and a second detection switch SWCH2, wherein one end of the first detection switch SWCH1 is connected to the neutral line; the first control end of the drive switch U1 is connected to the other end of the first detection switch SWCH1, the second control end is connected to the live line, the first output end of the second detection switch SWCH2 is connected to the detection signal input end of the external controller, and the second output end is connected to the second output end of the second detection switch SWCH2 and then connected to an external high-level signal (5V DC power supply); one end of the second detection switch SWCH2 is grounded, and the other end is connected to the control end of the controllable switch Q1. It should be noted that in the embodiment of the present invention, the first detection switch SWCH1 is a float switch, the drive switch U1 is a photoelectric coupler, the controllable switch Q1 is a triode, and the second detection switch SWCH2 is a metal probe. In actual applications, the selection of the above-mentioned components can also be adjusted as needed, as long as the same function can be achieved, and the present invention is not limited thereto.

[0022] In practical applications, since the float switch SWCH1 is directly connected to the live wire and the neutral wire and is in a strong current environment, and the second detection switch SWCH2 composed of a metal probe is powered by a DC power supply and is in a weak current environment, when the above-mentioned float switch SWCH1 and the second detection switch SWCH2 composed of a metal probe are arranged in the same water leakage detection circuit, it is necessary to realize the isolation of strong current and weak current through the photoelectric coupler U1 to ensure that the operation of the entire detection circuit is not interfered with each other and improve the accuracy of detection.

[0023] Specifically, in one embodiment, the water leakage detection circuit further includes a float installed at a preset water leakage position corresponding to the float switch SWCH1. In the embodiment of the present invention, the preset water leakage position is the overflow tank of the bottom cover of the dishwasher. Figure 1 The above-mentioned float is not shown.

[0024] Specifically, in one embodiment, if Figure 1 As shown, the water leakage detection circuit also includes: a rectifier diode D1 and a first resistor R1, wherein the forward end of the rectifier diode D1 is connected to the live wire, and the reverse end is connected to the second control end of the drive switch U1; one end of the first resistor R1 is connected to the other end of the first detection switch SWCH1, and the other end is connected to the second control end of the drive switch U1. In practical applications, the rectifier diode D1 functions to reduce the power consumption of the entire water leakage detection circuit by rectification, and the first resistor R1 is a current limiting resistor that plays the role of current limiting and voltage dividing. In practical applications, under the conditions of meeting power and withstand voltage, different types of packaged resistors can be used according to actual conditions to ensure circuit function and reliability, or multiple resistors can be used in series and parallel to achieve current limiting and voltage dividing functions.

[0025] Specifically, in one embodiment, if Figure 1 As shown, the water leakage detection circuit further includes: an alarm device P1, which is connected to the output end of the external controller. When the detection signal input end of the external controller receives a water overflow signal, an alarm control signal is generated to drive the alarm device P1 to alarm. In practical applications, the external controller is an MCU.

[0026] Specifically, in one embodiment, if Figure 1As shown, the second output end of the driving switch U1 is connected to the second output end of the second detection switch SWCH2 and then connected to a 5V power supply. The above-mentioned water leakage detection circuit also includes: a second resistor R2, a third resistor R3 and two filter capacitors C1 and C2 connected in parallel, wherein one end of the second resistor R2 is connected to the first output end of the driving switch U1, and the other end is respectively connected to one end of the third resistor R3, the detection signal input end of the external controller and one end of the two filter capacitors C1 and C2 connected in parallel, the other end of the third resistor R3 is grounded, and the other ends of the two filter capacitors C1 and C2 connected in parallel are grounded. In practical applications, the above-mentioned second resistor R2 and third resistor R3 have a voltage dividing effect, and the two filter capacitors C1 and C2 connected in parallel have a filtering effect to ensure the stability of the level signal output to the external controller.

[0027] like Figure 1 The working principle of the water leakage detection circuit shown is as follows:

[0028] There is no overflow when the dishwasher is working normally, so the overflow tank is dry and there is no water. SWCH1 and SWCH2 are in the disconnected state. At this time, the optocoupler U1 and the transistor Q1 are both in the disconnected state. The detection signal input terminal YISHUI_CTRL of the MCU detects a low level, and the MCU does not act. When the dishwasher leaks some water droplets due to long-term use and aging of some component interfaces, the leaked water drops into the bottom cover and flows into the overflow tank. As the amount of water increases, the buoyancy increases, the float is floated, the float switch SWCH1 is turned on, and the two metal probes SWCH2 is turned on after contacting water. The voltage divider of R2 and R3 detects a high level at this time. Since the detection signal input terminal of the MCU is triggered by a high level, it will trigger the MCU to output an alarm control signal to drive the alarm device P1 connected to the MCU output terminal to alarm, reminding the user that the dishwasher is leaking. In practical applications, when either SWCH1 or SWCH2 is turned on, YISHUI_CTRL will detect a high level. Even if one of the switches fails, the overflow phenomenon can be accurately detected, thereby improving detection reliability and avoiding unnecessary losses to the user's home.

[0029] It should be noted that in Figure 1 In the embodiment shown, the detection signal input terminal of the MCU is high-level triggered, that is, when the detection signal input terminal receives a high-level signal, it will trigger the MCU to detect a water leakage signal and issue an alarm. In actual applications, the MCU can also be set to a low-level trigger and the peripheral circuit structure can be modified accordingly. This is common knowledge among technicians in this field and the present invention is not limited to this.

[0030] Figure 2 FIG. 4 shows a schematic diagram of another water leakage detection circuit according to an embodiment of the present invention. Figure 2As shown, the water leakage detection circuit includes: a 5V DC power supply, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6 and two filter capacitors C3 and C4 connected in parallel, wherein the 5V DC power supply is connected to one end of the fifth resistor R5 and one end of the sixth resistor R6 respectively through the fourth resistor R4, the other end of the fifth resistor R5 is connected to the first output end of the drive switch U1, the other end of the sixth resistor R6 is connected to the detection signal input end of the external controller and one end of the two filter capacitors C3 and C4 connected in parallel, and the other end of the two filter capacitors C3 and C4 connected in parallel is grounded. In practical applications, the external controller is an MCU. Figure 2 In the water leakage detection circuit shown in the figure, the second output terminal of the driving switch U1 is connected to the second output terminal of the second detection switch SWCH2 and then grounded. The other components of the water leakage detection circuit are the same as those described above. Figure 1 The roles and functions of the corresponding components of the water leakage detection circuit shown are the same and will not be described in detail here.

[0031] like Figure 2 The working principle of the water leakage detection circuit shown is as follows:

[0032] When the dishwasher is working normally, there is no overflow phenomenon, so the overflow tank is dry and there is no water. SWCH1 and SWCH2 are in the disconnected state. At this time, the optocoupler U1 and the transistor Q1 are both in the disconnected state. The detection signal input terminal YISHUI_CTRL of the MCU detects a high level, and the MCU does not act. When the dishwasher leaks some water drops due to long-term use and the aging of some parts and interfaces, the leaked water drops into the bottom cover and flows into the overflow tank. As the amount of water increases, the buoyancy increases, the float is floated, the float switch SWCH1 is turned on, and after the two metal probes touch the water, SWCH2 is turned on, and R4, R5, and R6 divide the voltage. At this time, YISHUI_CTRL detects a low level. In actual applications, when any one of SWCH1 and SWCH2 is turned on, YISHUI_CTRL will detect a low level. Since the detection signal input terminal of the MCU is triggered by a low level, the MCU outputs an alarm control signal to drive the alarm device P1 connected to the MCU output terminal to alarm, reminding the user that the dishwasher is leaking. Even if one of the switches fails, water overflow can be accurately detected, thus improving detection reliability and avoiding unnecessary losses to the user's home.

[0033] It should be noted that in Figure 2 In the embodiment shown, the detection signal input terminal of the MCU is low-level triggered, that is, when the detection signal input terminal receives a low-level signal, it will trigger the MCU to detect a water leakage signal and issue an alarm. In actual applications, the MCU can also be set to a high-level trigger and the peripheral circuit structure can be modified accordingly. This is common knowledge among technicians in this field and the present invention is not limited to this.

[0034] Through the coordinated cooperation of the above-mentioned components, the water leakage detection circuit provided in the embodiment of the present invention jointly detects the water leakage of the dishwasher through the first detection switch and the second detection switch, and determines whether water leakage occurs through two detection methods, thereby improving the detection reliability and detection efficiency of the entire water leakage detection circuit, and avoiding the problem of being unable to perform overflow detection when the single float detection fails. The water leakage detection circuit provided in the embodiment of the present invention can be widely used in dishwashers or other household appliances that require water leakage detection, and the present invention is not limited thereto.

[0035] Although the embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations are all within the scope defined by the appended claims.

Claims

1. A water leakage detection circuit, characterized in that: include: A first detection switch (SWCH1), a drive switch (U1), a controllable switch (Q1) and a second detection switch (SWCH2), wherein: One end of the first detection switch (SWCH1) is connected to the neutral line; The first control end of the driving switch (U1) is connected to the other end of the first detection switch (SWCH1), the second control end is connected to the live wire, the first output end is connected to the first output end of the second detection switch (SWCH2) and then connected to the detection signal input end of the external controller, and the second output end is connected to the second output end of the second detection switch (SWCH2) and then connected to an external level signal; One end of the second detection switch (SWCH2) is grounded, and the other end is connected to the control end of the controllable switch (Q1); The first detection switch (SWCH1) is a float switch, and the water leakage detection circuit further comprises: a float installed at a preset water leakage detection position and arranged corresponding to the float switch; The second detection switch (SWCH2) is two probes installed at a preset water leakage detection position; the drive switch (U1) is a photoelectric coupler, and the preset water leakage position is the overflow tank of the bottom cover of the dishwasher; The water leakage detection circuit further comprises: a rectifier diode (D1) and a first resistor (R1), wherein: The forward end of the rectifier diode (D1) is connected to the live wire, and the reverse end is connected to the second control end of the drive switch (U1); One end of the first resistor (R1) is connected to the other end of the first detection switch (SWCH1), and the other end is connected to the second control end of the drive switch (U1).

2. The water leakage detection circuit according to claim 1, characterized in that: The probe is a metal probe.

3. The water leakage detection circuit according to claim 1, characterized in that: The controllable switch (Q1) is a triode.

4. The water leakage detection circuit according to claim 1, characterized in that: Also includes: An alarm device (P1) is connected to the output end of the external controller, and when the detection signal input end of the external controller receives a water overflow signal, an alarm control signal is generated to drive the alarm device (P1) to alarm.

5. The water leakage detection circuit according to any one of claims 1 to 4, characterized in that: When the external level signal is at a high level, the water leakage detection circuit further includes: a second resistor (R2), a third resistor (R3) and one or more filter capacitors connected in parallel, wherein: One end of the second resistor (R2) is connected to the first output end of the drive switch (U1), and the other end is respectively connected to one end of the third resistor (R3), the detection signal input end of the external controller and one end of the one or more filter capacitors connected in parallel, the other end of the third resistor (R3) is grounded, and the other end of the one or more filter capacitors connected in parallel is grounded.

6. The water leakage detection circuit according to any one of claims 1 to 4, characterized in that: When the external level signal is at a low level, the water leakage detection circuit further comprises: a DC power supply, a fourth resistor (R4), a fifth resistor (R5), a sixth resistor (R6) and one or more filter capacitors connected in parallel, wherein: The DC power supply is connected to one end of the fifth resistor (R5) and one end of the sixth resistor (R6) respectively through the fourth resistor (R4), the other end of the fifth resistor (R5) is connected to the first output end of the drive switch (U1), the other end of the sixth resistor (R6) is connected to the detection signal input end of the external controller and one end of the one or more filter capacitors connected in parallel, and the other end of the one or more filter capacitors connected in parallel is grounded.

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