Dry burning prevention control circuit and electric water heater

Abstract

The utility model relates to an anti-dry-burning control circuit and an electric water heater. The anti-dry-burning control circuit comprises a power supply module; the first switch unit is connected with the power supply module, and the first switch unit is used for controlling the on-off of a heating element; the detection module comprises a second switch unit, a first detection end and a second detection end, and the first detection end is connected with the second switch unit in series and then is connected with the power supply module; and the controller is respectively connected with the power supply module, the control end of the first switch unit, the control end of the second switch unit and the second detection end. The first detection end and the second detection end form a loop through water flow, and the controller can detect corresponding electric signals to control the heating element to start heating, so that the condition of dry burning of the electric water heater is effectively avoided, and energy consumption is reduced.

Description

Technical Field

[0001] The present application relates to the technical field of electronic circuits, and in particular to an anti-dry-burning control circuit and an electric water heater. Background Art

[0002] As people's living standards improve, the demand for household water heaters is also growing. Among them, existing electric water heaters generally have an anti-dry-burning function, which uses a water level monitoring device to detect the water level in the inner tank in real time. When the water level in the inner tank is full, the heating tube will be started to heat, thereby improving the safety of use. However, the water level monitoring device detects the water level in the inner tank in real time, which increases energy consumption. Utility Model Content

[0003] Based on this, it is necessary to provide an anti-dry burning control circuit and an electric water heater to address the above technical problems.

[0004] In the first aspect, the present application proposes an anti-dry-burning control circuit, which includes: a power supply module; a first switch unit, connected to the power supply module, and the first switch unit is used to control the on and off of a heating element; a detection module, the detection module includes a second switch unit, a first detection end and a second detection end, the first detection end is connected in series with the second switch unit and then connected to the power supply module; a controller, respectively connected to the power supply module, the control end of the first switch unit, the control end of the second switch unit, and the second detection end.

[0005] In the above-mentioned anti-dry-burning control circuit, the controller can disconnect the power supply of the detection module through the second switch unit, thereby reducing energy consumption.

[0006] In one embodiment, the detection module further includes a third switch unit, the second detection end is connected in series with the third switch unit and then connected to the controller, and the control end of the third switch unit is connected to the controller.

[0007] In one embodiment, the power module includes a rectifier and buck unit, an input end of the rectifier and buck unit is connected to the mains, and an output end of the rectifier and buck unit is connected to the first switch unit, the second switch unit, and the controller.

[0008] In one embodiment, the rectifier and step-down unit includes: a transformer and a rectifier bridge, the input end of the transformer is connected to the AC power, the output end of the transformer is connected to the input end of the rectifier bridge, and the output end of the rectifier bridge is connected to the first switch unit, the second switch unit, and the controller.

[0009] In one of the embodiments, the rectifier and buck unit further includes: a voltage stabilizer, wherein an input end of the voltage stabilizer is connected to the rectifier bridge, and an output end of the voltage stabilizer is connected to the second switch unit and the controller.

[0010] In one embodiment, the voltage stabilizer uses a voltage stabilizer chip model LM7805.

[0011] In one embodiment, the first switch unit is a relay.

[0012] In one embodiment, the second switch unit is a relay.

[0013] In one embodiment, the third switch unit is a relay.

[0014] In the second aspect, the present application proposes an electric water heater, comprising an inner tank and the anti-dry-burning control circuit described in the embodiment of the first aspect above, the inner tank is provided with a magnesium rod, a water outlet pipe and an electric heating tube, the first switch unit is connected to the electric heating tube, and the first switch unit is used to control the on and off of the electric heating tube; the first detection end is electrically connected to the magnesium rod, and the second detection end is arranged on the water outlet pipe, and the second detection end is used to contact the water in the water outlet pipe.

[0015] The above electric water heater connects the first detection end in the anti-dry-burn control circuit to the magnesium rod, and connects the second detection end to the water outlet pipe, so there is no need to open a hole in the inner tank to detect the water level, thereby reducing the risk of leakage in the inner tank. After detecting that the inner tank is full of water, the controller can disconnect the power supply of the detection module through the second switch unit, thereby reducing energy consumption; at the same time, after detecting that the inner tank is full of water, for example, during the heating process, the controller promptly disconnects the voltage applied to the magnesium rod through the second switch unit, which can effectively avoid the situation where the magnesium rod is accelerated in consumption and leads to a reduction in life. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the conventional technology, the drawings required for use in the embodiments or the conventional technology descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0017] FIG1 is a block diagram of an anti-dry burning control circuit in one embodiment;

[0018] FIG2 is a module diagram of an anti-dry burning control circuit in another embodiment;

[0019] FIG3 is a module diagram of an anti-dry burning control circuit in yet another embodiment;

[0020] FIG4 is a circuit diagram of a rectifier and voltage-reducing unit in one embodiment;

[0021] FIG5 is a circuit diagram of an anti-dry burning control circuit in one embodiment;

[0022] FIG. 6 is a schematic diagram of an electric water heater in one embodiment.

[0023] Description of reference numerals:

[0024] The power module 110, the first switch unit 120, the detection module 130, the controller 140, the second switch unit 131, the first detection end 132, the second detection end 133, the third switch unit 134, the rectifier and step-down unit 111, the inner tank 200, the anti-dry burning control circuit 100, the magnesium rod 210, the water outlet pipe 220, and the water inlet pipe 230. DETAILED DESCRIPTION

[0025] In order to facilitate understanding of the present application, the present application will be described more fully below with reference to the relevant drawings. Embodiments of the present application are provided in the drawings. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present application more thorough and comprehensive.

[0026] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0027] It can be understood that the terms "first", "second", etc. used in the present application can be used in this article to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish the first element from another element.

[0028] Spatial relationship terms such as "under", "below", "below", "under", "above", "above", etc., may be used herein to describe the relationship between an element or feature shown in the figures and other elements or features. It should be understood that in addition to the orientations shown in the figures, spatial relationship terms also include different orientations of the device in use and operation. For example, if the device in the accompanying drawings is turned over, the element or feature described as "under other elements" or "under it" or "under it" will be oriented as "on" other elements or features. Therefore, the exemplary terms "under" and "under" may include both upper and lower orientations. In addition, the device may also include additional orientations (e.g., rotated 90 degrees or other orientations), and the spatial descriptors used herein are interpreted accordingly.

[0029] It should be noted that when an element is considered to be "connected" to another element, it can be directly connected to the other element, or connected to the other element through an intermediate element. In addition, the "connection" in the following embodiments should be understood as "electrical connection", "communication connection", etc. if there is transmission of electrical signals or data between the connected objects.

[0030] When used herein, the singular forms "a", "an", and "said / the" may also include plural forms, unless the context clearly indicates otherwise. It should also be understood that the terms "include / comprise" or "have" and the like specify the presence of stated features, wholes, steps, operations, components, parts, or combinations thereof, but do not exclude the possibility of the presence or addition of one or more other features, wholes, steps, operations, components, parts, or combinations thereof. At the same time, the term "and / or" used in this specification includes any and all combinations of the relevant listed items.

[0031] In one embodiment, as shown in FIG1 , a dry-burn prevention control circuit is provided, including: a power module 110, a first switch unit 120, a detection module 130 and a controller 140, wherein the first switch unit 120 is connected to the power module 110, and the first switch unit 120 is used to control the on and off of the heating element; the detection module 130 includes a second switch unit 131, a first detection end 132 and a second detection end 133, and the first detection end 132 is connected in series with the second switch unit 131 and then connected to the power module 110; the controller 140 is respectively connected to the power module 110, the control end of the first switch unit 120, the control end of the second switch unit 131, and the second detection end 133.

[0032] Specifically, the power module 110 is used to supply power to the entire anti-dry-burning control circuit. The power module 110 can output DC voltages of different sizes, for example, +5V DC voltage, +12V DC voltage, etc. The first switch unit 120, the detection module 130 and the controller 140 can obtain voltages of corresponding sizes according to their own needs. The first switch unit 120 is respectively connected to the power module 110, the heating element and the controller 140. The control end of the first switch unit 120 is used to receive the heating signal of the controller 140. The first switch unit 120 is used to generate on-off according to the heating signal, thereby controlling the on-off of the heating element. For example, the heating element is respectively connected to the mains and the first switch unit 120. When the first switch unit 120 is closed, the heating element starts to heat; when the first switch unit 120 is disconnected, the heating element stops heating.

[0033] It is understandable that the above-mentioned anti-dry-burning control circuit has two flexible detection terminals (the first detection terminal 132 and the second detection terminal 133), which can be installed according to actual needs. For example, when the above-mentioned anti-dry-burning control circuit is applied to an electric water heater, the first detection terminal 132 and the second detection terminal 133 can be installed on the inner tank 200 at the same time. When the water level of the inner tank 200 is submerged by the first detection terminal 132 and the second detection terminal 133 at the same time, the first detection terminal 132 and the second detection terminal 133 are connected to form a loop, and the controller 140 receives a full water signal. The controller 140 controls the heating element to start heating through the first switch unit 120. When the water level of the inner tank 200 does not submerge the first detection terminal 132 and the second detection terminal 133 at the same time, the first detection terminal 132 and the second detection terminal 133 are disconnected, the controller 140 does not receive a full water signal, and the heating element does not start heating, thereby achieving the effect of anti-dry-burning.

[0034] In other embodiments, the first detection end 132 can also be installed on the inner tank 200, and the second detection end 133 can be installed on the water outlet pipe 220; in addition, the first detection end 132 can also be installed on the magnesium rod 210, and the second detection end 133 can be installed on the water outlet pipe 220.

[0035] After detecting that the inner pot 200 is full of water, for example, during the heating process, the controller 140 can disconnect the power supply of the detection module 130 through the second switch unit 131, thereby reducing energy consumption.

[0036] The following is a specific example to illustrate that when the anti-dry-burning control circuit of the present application is applied to an electric water heater, the first detection end 132 of the detection module 130 is electrically connected to the magnesium rod 210, and the second detection end 133 is arranged at the water outlet pipe 220, and the second detection end 133 is used to contact the water in the water outlet pipe 220. The first detection end 132 is connected to the power module 110 after being connected in series with the second switch unit 131, and is used to receive the voltage signal output by the power module 110.

[0037] In one embodiment, when it is necessary to detect the water level in the inner tank 200, the controller 140 sends a switch signal to the control end of the second switch unit 131, and the second switch unit 131 is closed. If the water level in the inner tank 200 exceeds the water outlet pipe 220, the water will flow through the upper end of the water outlet pipe 220 to the second detection end 133. At this time, the first detection end 132 and the second detection end 133 form a loop through the water flow. When the first detection end 132 receives the voltage signal output by the power module 110, the controller 140 will receive a high-level voltage signal. When the controller 140 receives a high-level voltage signal, it means that the water level in the inner tank 200 meets the heating requirements. At this time, the controller 140 controls the first switch unit 120 to close, the heating element is powered on and starts heating, thereby heating the water stored in the inner tank 200; correspondingly, if the controller 140 does not receive a high-level voltage signal, it means that the first detection end 132 and the second detection end 133 do not form a loop through the water flow. At this time, the water storage in the inner tank 200 is insufficient and the heating element does not start heating.

[0038] It is understandable that after detecting that the inner tank 200 is full of water, for example during the heating process, the controller 140 promptly disconnects the voltage applied to the magnesium rod 210 through the second switch unit 131, which can effectively avoid the situation where the magnesium rod 210 is accelerated in consumption and thus reduces its lifespan.

[0039] In one embodiment, as shown in FIG. 2 , the detection module 130 further includes a third switch unit 134, the second detection terminal 133 is connected in series with the third switch unit 134 and then connected to the controller 140, and the control end of the third switch unit 134 is connected to the controller 140. Specifically, the controller 140 can send a switch signal to the control end of the third switch unit 134, and the third switch unit 134 can be interrupted or turned on according to the switch signal, thereby controlling the on-off of the second detection terminal 133 and the controller 140 to adjust whether the controller 140 can receive the voltage signal. It can be understood that in this embodiment, the controller 140 sends a switch signal to the second switch unit 131 and the third switch unit 134 synchronously through a signal output port, and the second switch unit 131 and the third switch unit 134 will be synchronously interrupted or turned on. Through this setting, the connection between the controller 140 and the first detection terminal 132 and the second detection terminal 133 can be cut off, effectively avoiding damage to the controller 140 in the case of leakage of the heating element. In some other embodiments, the controller 140 may send switch signals to the second switch unit 131 and the third switch unit 134 respectively through two signal output ports.

[0040] In one embodiment, the first switch unit 120 uses a relay; and / or the second switch unit 131 uses a relay; and / or the third switch unit 134 uses a relay. Specifically, in this embodiment, at least one of the first switch unit 120, the second switch unit 131, and the third switch unit 134 can use a relay, for example, the first switch unit 120 uses a relay, and the second switch unit 131 and the third switch unit 134 use a switch tube; for another example, the first switch unit 120 and the second switch unit 13 use a relay, and the third switch unit 134 uses a switch tube. Among them, the switch tube can be a triode or an optical coupler, which can be selected according to the specific design.

[0041] In one embodiment, as shown in FIG3 , the power module 110 includes a rectifier and buck unit 111, the input end of the rectifier and buck unit 111 is connected to the mains, and the output end of the rectifier and buck unit 111 is connected to the first switch unit 120, the second switch unit 131, and the controller 140. Specifically, the rectifier and buck unit 111 is used to rectify and buck the input AC voltage, thereby outputting a plurality of DC voltages of different magnitudes, for example, +5V DC voltage, +12V DC voltage, etc., to provide different voltages to the first switch unit 120, the detection module 130, and the controller 140. In some other embodiments, the power module 110 may not be provided with the rectifier and buck unit 111, and it may output the corresponding DC voltage through a battery.

[0042] In one embodiment, as shown in Figure 4, the rectifier and step-down unit 111 includes: a transformer T1 and a rectifier bridge B1, the input end of the transformer T1 is connected to the AC power, the output end of the transformer T1 is connected to the input end of the rectifier bridge B1, and the output end of the rectifier bridge B1 is connected to the first switch unit 120, the second switch unit 131, and the controller 140.

[0043] Specifically, the input end of the transformer T1 is connected to the mains and is used to receive an AC voltage. The transformer T1 can step down the input AC voltage, and the stepped-down AC voltage is transmitted from the output end of the transformer T1 to the input end of the rectifier bridge B1. The rectifier bridge B1 is used to rectify the stepped-down AC voltage into a DC voltage. The output end of the rectifier bridge B1 is respectively connected to the first switch unit 120, the second switch unit 131, and the controller 140, and is used to output a first DC voltage thereto. In some embodiments, the first DC voltage may be a +12V DC voltage, and the first switch unit 120, the second switch unit 131, and the controller 140 may work under the action of a +12V DC voltage.

[0044] In one embodiment, as shown in FIG4 , the rectifier-step-down unit 111 further includes: a voltage regulator U1, the input end of the voltage regulator U1 is connected to the rectifier bridge B1, and the output end of the voltage regulator U1 is connected to the second switch unit 131 and the controller 140. Specifically, the input end of the voltage regulator U1 receives the DC voltage and then steps it down, and finally outputs the stepped-down DC voltage from the output end of the voltage regulator U1, and the output end of the voltage regulator U1 is respectively connected to the second switch unit 131 and the controller 140, for outputting the second DC voltage thereto. In some embodiments, the voltage regulator U1 uses a voltage regulator chip of model LM7805. In some embodiments, the second DC voltage is a DC voltage of +5V, and the second switch unit 131 and the controller 140 can work under the action of the DC voltage of +5V.

[0045] In one embodiment, as shown in Fig. 4, the rectifying and step-down unit 111 further includes a capacitor C1, one end of which is connected to the output end of the rectifier bridge B1, and the other end of which is grounded. By setting the capacitor C1, clutter can be filtered out to make the current more stable.

[0046] The following is a detailed description of the anti-dry burning control circuit of the present application with a specific embodiment. In this embodiment, the first switch unit 120 includes a first relay J1, the second switch unit 131 includes a second relay J2, and the third switch unit 134 includes a third relay J3. As shown in Figure 5, the input end of the transformer T1 is connected to the neutral line and the live line respectively, and is used to receive the AC voltage. The transformer T1 steps down the AC voltage and outputs it to the rectifier bridge B1. After rectification by the rectifier bridge B1, a 12V DC voltage is obtained, and then the voltage is stepped down by the voltage regulator U1 to obtain a 5V DC voltage. The 5V DC voltage is used to supply power to the power supply end (pin 1) of the controller 140, and output a 5V voltage signal to the contact group of the second relay J2. The 12V DC voltage is connected to the coil groups of the first relay J1, the second relay J2 and the third relay J3 respectively. The switch signal output end (pin 3) of the controller 140 is connected to the coil groups of the second relay J2 and the third relay J3 respectively, and is used to control the on and off of the two relays. The heating signal output terminal (pin 2) of the controller 140 is connected to the coil group of the first relay J1 and is used to control the on and off of the first relay J1. When the water level in the inner tank 200 of the electric water heater exceeds the water outlet pipe 220, the water will flow through the upper end of the water outlet pipe 220 to the second detection terminal 133. At this time, the first detection terminal 132 and the second detection terminal 133 form a loop through the water flow. When the second relay J2 and the third relay J3 are turned on, the signal input terminal (pin 4) of the controller 140 will receive a high-level voltage signal. After the controller 140 receives the high-level voltage signal, it means that the water level in the inner tank 200 meets the heating requirements. At this time, the controller 140 controls the first relay J1 to close, and the heating element starts to work to heat the water stored in the inner tank 200. In one embodiment, as shown in Figure 6, the present application also proposes an electric water heater, including an inner tank 200 and the anti-dry burning control circuit 100 in the above embodiment, the inner tank 200 is provided with a magnesium rod 210, a water outlet pipe 220 and an electric heating pipe (not shown in the figure), the first switch unit 120 is connected to the electric heating pipe, and the first switch unit 120 is used to control the on and off of the electric heating pipe; the first detection end 132 is electrically connected to the magnesium rod 210, and the second detection end 133 is arranged on the water outlet pipe 220, and the second detection end 133 is used to contact the water in the water outlet pipe 220.

[0047] Specifically, the magnesium rod 210 is used to protect the inner tank 200 and the electric heating tube in the electric water heater, while softening the water quality and preventing excessive scale, thereby extending the service life of the electric water heater. In some embodiments, the magnesium rod 210 can be a resistance magnesium rod 210 to prevent the magnesium rod 210 from being consumed quickly. The second detection end 133 is arranged at the lower end opening of the water outlet pipe 220, that is, at the water outlet; in one embodiment, the second detection end 133 is insulated and installed on the water outlet pipe 220. The electric heating tube is used to heat the stored water in the inner tank 200. It can be understood that the electric water heater also includes: a water inlet pipe 230, which is used to inject water into the inner tank 200.

[0048] The electric water heater in this embodiment connects the first detection end 132 in the detection module 130 with the magnesium rod 210, and sets the second detection end 133 in the water outlet pipe 220, so there is no need to open a hole in the inner tank 200 to detect the water level, thereby reducing the risk of water leakage in the inner tank 200. When the water level in the inner tank 200 exceeds the water outlet pipe 220, the water will flow through the upper end of the water outlet pipe 220 to the second detection end 133. At this time, the magnesium rod 210 and the second detection end 133 form a loop through the water flow. When there is an input voltage at the first detection end 132, the signal input end of the controller 140 will detect a high-level voltage signal, and in this case, the first switch unit 120 will be controlled to be turned on, and the electric heating tube will start heating.

[0049] Among them, after detecting that the inner tank 200 is full of water, the controller 140 can disconnect the power supply of the detection module 130 through the second switch unit 131, thereby reducing energy consumption; at the same time, after detecting that the inner tank 200 is full of water, for example, during the heating process, the controller 140 promptly disconnects the voltage applied to the magnesium rod 210 through the second switch unit 131, which can effectively avoid the accelerated consumption of the magnesium rod 210 and the resulting reduction in lifespan.

[0050] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "specific embodiments", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic descriptions of the above terms do not necessarily refer to the same embodiment or example.

[0051] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0052] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be construed as limiting the scope of the patent application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent application shall be subject to the attached claims.

Claims

1. A dry burning prevention control circuit, characterized in that: The anti-dry burning control circuit (100) comprises: Power module (110); A first switch unit (120), connected to the power module (110), the first switch unit (120) being used to control the on and off of the heating element; A detection module (130), the detection module (130) comprising a second switch unit (131), a first detection end (132) and a second detection end (133), the first detection end (132) being connected in series with the second switch unit (131) and then connected to the power module (110); The controller (140) is respectively connected to the power module (110), the control end of the first switch unit (120), the control end of the second switch unit (131), and the second detection end (133).

2. The anti-dry burning control circuit according to claim 1, characterized in that: The detection module (130) further comprises a third switch unit (134); the second detection end (133) is connected in series with the third switch unit (134) and then connected to the controller (140); and the control end of the third switch unit (134) is connected to the controller (140).

3. The anti-dry burning control circuit according to claim 1, characterized in that: The power module (110) comprises a rectifier and buck unit (111), wherein an input end of the rectifier and buck unit (111) is connected to the mains, and an output end of the rectifier and buck unit (111) is connected to the first switch unit (120), the second switch unit (131), and the controller (140).

4. The anti-dry burning control circuit according to claim 3, characterized in that: The rectifier and voltage-reducing unit (111) comprises: a transformer (T1) and a rectifier bridge (B1); an input end of the transformer (T1) is connected to the mains; an output end of the transformer (T1) is connected to an input end of the rectifier bridge (B1); and an output end of the rectifier bridge (B1) is connected to the first switch unit (120), the second switch unit (131), and the controller (140).

5. The anti-dry burning control circuit according to claim 4, characterized in that: The rectifier and voltage-reducing unit (111) further comprises: a voltage stabilizer (U1), wherein an input end of the voltage stabilizer (U1) is connected to the rectifier bridge (B1), and an output end of the voltage stabilizer (U1) is connected to the second switch unit (131) and the controller (140).

6. The anti-dry burning control circuit according to claim 5, characterized in that: The voltage regulator (U1) adopts a voltage regulator chip of model LM7805.

7. The anti-dry burning control circuit according to claim 1, characterized in that: The first switch unit (120) is a relay.

8. The anti-dry burning control circuit according to claim 1, characterized in that: The second switch unit (131) is a relay.

9. The anti-dry burning control circuit according to claim 2, characterized in that: The third switch unit (134) is a relay.

10. An electric water heater, characterized in that: The invention comprises an inner pot (200) and an anti-dry burning control circuit (100) according to any one of claims 1 to 9, wherein the inner pot (200) is provided with a magnesium rod (210), a water outlet pipe (220) and an electric heating pipe, the first switch unit (120) is connected to the electric heating pipe, and the first switch unit (120) is used to control the on and off of the electric heating pipe; the first detection end (132) is electrically connected to the magnesium rod (210), the second detection end (133) is arranged on the water outlet pipe (220), and the second detection end (133) is used to contact water in the water outlet pipe (220).

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