Liquid heater

Abstract

The utility model provides a liquid heater, which relates to a liquid heater and comprises a pot body containing liquid nonmetal and a first detection plate arranged on the outer wall of the pot body, a capacitance pole piece is arranged on the first detection plate, the capacitance pole piece is used for detecting the liquid level, and the liquid heater comprises a metal shielding belt surrounding the outer wall of the pot body and grounded. The capacitor pole piece is located between the metal shielding belt and the outer wall of the kettle body, and the width of the metal shielding belt is larger than that of the capacitor pole piece. The liquid heater is used for solving the technical problem that parasitic capacitance interference from the front face of the capacitor pole piece is difficult to reduce in the prior art under the condition that the contact face of the capacitor pole piece and the liquid heater is an arc face.

Description

Technical Field

[0001] The utility model relates to the technical field of liquid heaters, in particular to a liquid heater. Background Art

[0002] In modern kitchen life, liquid heaters are increasingly used, and foam easily overflows when making drinks with liquid heaters.

[0003] In order to avoid the problem of foam overflow, the original liquid heater achieved overflow prevention through the form of contact electrodes or probes. For example, the prior art CN90100704.8 discloses a fully automatic household soybean milk maker, in which a probe is provided on the lid of the liquid heater. The probe detects whether the foam has overflowed by detecting the resistance formed by the foam adhering to the wall of the heating container or between the probes. However, for a single beverage, the beverage will become thick after boiling, and the beverage is likely to remain between the probe and the wall of the inner tank, and the resistance of the beverage itself will change when it becomes thick, affecting the accuracy of the probe detection. In addition, the probe needs to go deep into the heating container to contact the beverage, which is not conducive to the cleaning of the heating container.

[0004] In view of these limitations of contact electrodes, the design of liquid heaters gradually adopts non-contact capacitor electrodes for foam detection. These capacitor electrodes are installed on the outer wall of the heating container. There is a significant difference in the original signal of the non-contact capacitor electrodes in the presence and absence of water. When there is no water at the height of the capacitor electrode, the medium of the capacitor electrode is air, and the dielectric constant of air is relatively low, usually about 1. Therefore, in the absence of water, the capacitor electrode outputs a lower original signal. When there is water at the height of the capacitor electrode, water is used as the medium, and the dielectric constant of water is much higher than that of air, usually around 80. Therefore, in the presence of water, the original signal output by the capacitor electrode will also be enhanced.

[0005] Therefore, the non-contact capacitor electrode detects the water level and the presence and height of foam through the change of dielectric constant. This detection method does not require direct contact with the liquid, is safe and reliable, and is gradually being widely used in liquid heaters. For example, the prior art CN97225228.2 discloses a multifunctional control device for preventing overflow of an electric heating film glass cup (pot), including three conductive film liquid level sensor elements (capacitor electrodes) made on the outer surface of the electric heating film glass cup. This non-contact detection not only avoids the need for direct contact detection devices between foam and liquid, reduces the difficulty of cleaning, but also improves the accuracy of detection and the reliability of the equipment, thereby adjusting the heating state of the heating element when the amount of foam exceeds a predetermined threshold, such as reducing the heating power or stopping heating, to protect the safety of the liquid heater and the user.

[0006] In the process of detecting foam, the capacitance value generated by the non-contact capacitor electrode is easily affected by the human body or other interference, which is also called parasitic capacitance (refers to other unexpected capacitances outside the measured capacitance, which will affect the measurement results). Therefore, in the prior art CN202410210628.8, the capacitor electrodes are all attached to the front surface of the substrate facing the side of the glass cup body, and the control chip and the output terminal are arranged on the rear surface of the substrate, and the control chip and the output terminal are both located below the water level detection area. At the same time, a mesh shielding layer is also attached to the substrate, and the mesh shielding layer is grounded. The mesh shielding layer includes a first shielding layer attached to the rear surface of the substrate and a second shielding layer attached to the front surface of the substrate. The second shielding layer is enclosed along the edge of the substrate on the outside of the water level detection area and the anti-overflow detection area, and the lower side of the second shielding layer is open. The mesh shielding layer is a copper-clad mesh, which is used to shield the inductive interference of external parasitic capacitance on the capacitor electrode.

[0007] The prior art sets a shielding layer on the edge of the capacitor electrode on the front side of the substrate, and sets a shielding layer on the back side of the substrate, so that the sensing direction of the capacitor electrode is concentrated on the front side of the capacitor electrode. However, the front side of the capacitor electrode is also affected by parasitic capacitance. For example, the Texas Instruments TIDA-00317 capacitive liquid level sensor reference design points out that when a human hand is 50mm in front of the capacitor electrode, it still interferes with the detection value of the capacitor electrode; especially when the water level is low, the parasitic capacitance interferes more with the capacitor electrode.

[0008] In order to solve the above technical problems, Texas Instruments proposed anisotropic differential technology in the TIDA-00317 capacitive liquid level sensor reference design. Capacitor electrodes are provided on the front and back sides of the substrate. The capacitor electrode on the front side is used to detect the liquid level and foam to output a positive capacitance signal, and the capacitor electrode on the back side is used to provide an out-of-phase capacitance signal. The positive capacitance signal and the out-of-phase capacitance signal are differentially calculated to reduce the impact of parasitic capacitance caused by the proximity of the human body.

[0009] However, the inner tank of the existing liquid heater is often cylindrical, conical or elliptical, and its contour includes a large number of arcs, so that the contact surface between the capacitor electrode and the inner tank is an arc surface. In actual use, it is found that the anisotropic differential technology requires symmetrical front and rear capacitor electrodes, which is difficult to achieve when the contact surface is an arc surface. Utility Model Content

[0010] The utility model aims to provide a liquid heater to solve the technical problem that when the contact surface between the capacitor electrode and the liquid heater is an arc surface, the prior art is difficult to reduce the parasitic capacitance interference from the front side of the capacitor electrode.

[0011] An embodiment of the present application provides a liquid heater, including a non-metallic kettle body for holding liquid, and a first detection plate arranged on the outer wall of the kettle body, the first detection plate is provided with a capacitor electrode, the capacitor electrode is used to detect the liquid level, and includes a metal shielding belt that surrounds the outer wall of the kettle body and is grounded, the capacitor electrode is located between the metal shielding belt and the outer wall of the kettle body, and the width of the metal shielding belt is greater than the width of the capacitor electrode.

[0012] In some embodiments of the present invention, there are a plurality of capacitor electrodes, and the plurality of capacitor electrodes are disposed around the outer wall of the kettle body along a metal shielding belt.

[0013] In some embodiments of the utility model, a handle and a fastener are further provided on the outer side of the kettle body, the metal shielding belt is provided with a connecting hole, and the fastener passes through the connecting hole and is installed to the handle.

[0014] In some embodiments of the present invention, there are a plurality of the capacitor pole pieces, and the plurality of the capacitor pole pieces are symmetrically arranged on both sides of the fastener.

[0015] In some embodiments of the present invention, a gap is left between the metal shielding tape and the first detection plate.

[0016] In some embodiments of the present invention, the metal shielding belt is installed on the kettle body through sealant, and the capacitor electrode is located in the sealant.

[0017] In some embodiments of the utility model, a bracket is provided between the metal shielding belt and the outer wall of the kettle body, a mounting groove is provided on the side of the bracket facing the outer wall of the kettle body, and the capacitor electrode is arranged in the mounting groove.

[0018] In some embodiments of the utility model, the capacitor electrode is fixed to the outer wall of the kettle body, and the metal shielding belt is in contact with the first detection plate; or,

[0019] The capacitor electrode is fixed to the metal shielding belt, and the first detection plate is in contact with the outer wall of the kettle body.

[0020] In some embodiments of the present invention, a second detection plate is separately provided at the lower side of the first detection plate.

[0021] In some embodiments of the present invention, the first detection plate is made of flexible material.

[0022] Compared with the prior art, the embodiments of the present invention have at least the following advantages or beneficial effects:

[0023] The metal shielding belt is grounded and arranged around the outer wall of the kettle body, and the capacitor electrode is located between the metal shielding belt and the kettle body. The metal shielding belt minimizes the interference of the parasitic capacitance outside the kettle body on the capacitor electrode, especially the annular metal shielding belt, which reduces the interference of the parasitic capacitance outside the kettle body on the front side of the capacitor electrode.

[0024] In some embodiments, there are multiple capacitor electrodes, which are arranged around the outer wall of the kettle body along a metal shielding belt, so that the liquid heater can detect the liquid level (water level and foam) from different positions, thereby improving the uniformity of liquid level detection.

[0025] In addition to reducing the interference of parasitic capacitance, the metal shielding tape can also be used for the installation and connection of other components (such as handles). BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic diagram of the structure of the kettle body, handle and metal shielding belt of an embodiment of the present application.

[0027] Figure 2 It is a structural schematic diagram of the metal shielding belt and the first detection plate installed on the kettle body in an embodiment of the present application.

[0028] Figure 3 It is a structural schematic diagram of the metal shielding belt and the first detection plate of the embodiment of the present application installed on the kettle body through sealant.

[0029] Figure 4 It is a schematic diagram of the structure of the metal shielding belt and the connection hole of the embodiment of the present application.

[0030] Figure 5 It is a schematic diagram of the structure in which the metal shielding belt and the handle of the embodiment of the present application are installed through fasteners.

[0031] Figure 6 It is a structural schematic diagram of the mounting portion, mounting groove and connecting portion in the bracket of the embodiment of the present application.

[0032] Figure 7 It is a schematic diagram of the structure in which the metal shielding belt and the first detection plate of the embodiment of the present application are matched through the sealant gap.

[0033] Icon: 1-pot body, 101-handle, 111-fastener, 102-sealant, 2-metal shielding tape, 201-connecting hole, 3-first detection plate, 401-installation part, 411-installation groove, 402-connecting part. DETAILED DESCRIPTION

[0034] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0035] like Figure 1-Figure 7 As shown, in this embodiment, the liquid heater includes a metal shielding belt 2 which surrounds the outer wall of the kettle body 1 and is grounded, and the capacitor electrode is located between the metal shielding belt 2 and the outer wall of the kettle body 1. The width of the metal shielding belt 2 is greater than the width of the capacitor electrode, thereby reducing the influence of the front and rear parasitic capacitances on the capacitor electrode on the first detection plate 3, thereby improving the accuracy and stability of the capacitor electrode detection.

[0036] Among them, parasitic capacitance refers to other unexpected capacitance existing outside the measured capacitance, which will affect the measurement result of the capacitor electrode on the first detection board 3. For example, the capacitance value generated between the charge on a person's hand and the capacitor electrode can be called parasitic capacitance.

[0037] In this embodiment, the metal shielding belt 2 is a conductive member made of a conductive material, and the metal shielding belt 2 is grounded and maintained at the same potential as the ground, thereby neutralizing the electric field caused by the charge on the human hand, preventing the formation of an electric field between the capacitor electrode and the human hand, thereby reducing the generation of parasitic capacitance. In this embodiment, the metal shielding belt 2 is grounded and arranged around the outer wall of the kettle body 1, and the capacitor electrode is located between the metal shielding belt 2 and the kettle body 1. The metal shielding belt 2 minimizes the interference of the parasitic capacitance outside the kettle body on the capacitor electrode, especially the annular metal shielding belt 2, which reduces the interference of the parasitic capacitance outside the kettle body 1 on the front side of the capacitor electrode.

[0038] In addition, the electric field generated by the capacitor electrode located inside the metal shielding belt 2 is blocked by the metal shielding cover, so that these electric fields will not propagate outward. This can prevent the electric field of the capacitor electrode from interacting with objects or components outside the kettle body 1, further reducing parasitic capacitance. At the same time, the width of the metal shielding belt 2 is greater than the width of the capacitor electrode, and the metal shielding belt 2 wraps the first detection plate 3 as much as possible to reduce the interference of parasitic capacitance.

[0039] In actual use, it is found that in the prior art, a detection plate is often only provided on one side of the kettle body 1. However, when the width of the detection plate is insufficient or there is an error in the installation of the detection plate and the kettle body 1, the detection distance of the detection plate is shortened. If the foam generated by the beverage in the kettle body 1 is uneven, the detection plate on one side cannot reliably detect the foam, which may cause foam overflow.

[0040] In order to solve the above problems, in some embodiments of the present embodiment, there are multiple capacitor electrodes, and multiple capacitor electrodes are arranged around the outer wall of the kettle body 1 along the metal shielding belt 2, so that the liquid heater can detect the liquid level (water level and foam) from different positions, thereby improving the uniformity of liquid level detection. In some embodiments, there can be only one first detection plate 3, and all capacitor electrodes can be installed on the same first detection plate 3; there can also be multiple first detection plates 3, the number of first detection plates 3 is less than the number of capacitor electrodes, and the first detection plate 3 is provided with a single or multiple capacitor electrodes; the first detection plate 3 can also correspond to the capacitor electrodes one by one.

[0041] In some embodiments of the present embodiment, in addition to reducing the interference of parasitic capacitance, the metal shielding tape 2 can also be used for the installation and connection of other components. The kettle body 1 (often made of glass) may be provided with a heating device (such as a heating tube) at the bottom of the kettle body 1, and also includes a handle 101, which can be installed to the outside of the kettle body 1 through the metal shielding tape 2 and the fastener 111. The fastener 111 can be a bolt, and the handle 101 can be provided with a bolt hole for installing the bolt. The two ends of the metal shielding tape 2 in the length direction can be provided with connecting holes 201. When the metal shielding tape 2 is installed on the outside of the kettle body 1, the connecting holes 201 at both ends can be coaxial, so that the bolts can pass through the two connecting holes 201. When installing the handle 101, the bolts can pass through the connecting holes 201 at both ends of the metal shielding tape 2 and be screwed into the bolt holes of the handle 101, so that the handle 101 can be installed through the metal shielding tape 2. In some embodiments, if the fastener 111 is a conductive member, the metal shielding tape 2 can be grounded through the fastener 111.

[0042] It was also found during use that the handle 101 is installed through the metal shielding belt 2. When the user holds the handle 101, the metal shielding belt 2 is on the side away from the fastener 111, and the contact force between the metal shielding belt 2 and the outer side of the kettle body 1 is larger; the metal shielding belt 2 is on the side close to the fastener 111, and the contact force between the metal shielding belt 2 and the outer side of the kettle body 1 is smaller. In the case of multiple capacitor electrodes, it is easy to cause uneven force on different capacitor electrodes, especially the forces on different capacitor electrodes are different. When receiving the signal generated by the capacitor electrode, it is necessary to calibrate and compensate the signal generated by the capacitor electrode separately.

[0043] In order to solve the above problem, in some embodiments of the above implementation mode, the multiple capacitor electrodes are symmetrically arranged on both sides of the fastener 111. At the same time, the metal shielding belt 2 on both sides of the fastener 111 is subjected to relatively symmetrical force. In fact, the capacitor electrode on one side is calibrated and compensated first, and the symmetrical side only needs to use the same compensation, thereby reducing the technical problem of time-consuming calibration and compensation of multiple capacitor electrodes when the metal shielding belt 2 is also used as a mounting part.

[0044] In addition to the above installation methods, different installation methods of the first detection plate 3, different matching relationships between the metal shielding belt 2 and the first detection plate 3, and different installation methods of the metal shielding belt 2 can be selected according to different usage scenarios and needs. Among them, the installation methods of the first detection plate 3 include at least the following two: 1. The first detection plate 3 is installed on the kettle body 1, and the metal shielding belt 2 is close to or in contact with the first detection plate 3; 2. The first detection plate 3 is installed on the metal shielding belt 2, and then the metal shielding belt 2 is installed so that the first detection plate 3 is close to or in contact with the kettle body 1.

[0045] For example: 1. The first detection plate 3 is first installed on the outer wall of the kettle body 1, and then the metal shielding belt 2 is installed, so that the metal shielding belt 2 is close to or abuts against the first detection plate 3. In this installation method, the metal shielding belt 2 is directly installed on the outer side of the kettle body 1, and the installation process is relatively simple.

[0046] In some implementations of the above embodiments, the first detection plate 3 can be installed to the outer wall of the kettle body 1 by means of a sealant 102 or the like. The first detection plate 3 can also be installed to the outer wall of the kettle body 1 by a bracket. Specifically, the first detection plate 3 can be first installed in the mounting groove 411 of the bracket facing the outer wall of the kettle body 1, and then the bracket is installed to the outer wall of the kettle body 1, and finally the metal shielding belt 2 is installed to fix the first detection plate 3 and the bracket. In some implementations, the bracket can be an integrated C-shaped structure, and the bracket can be made of insulating and elastic materials such as plastic. The bracket includes mounting portions 401 that are spaced and provided with mounting grooves 411, and the mounting portions 401 are connected by connecting portions 402, and the width (or thickness) of the mounting portion 401 is greater than the width (or thickness) of the connecting portion 402, so that the connecting portion 402 is easier to deform than the mounting portion 401, so that the integrated C-shaped bracket is opened and then restored to be installed to the kettle body 1.

[0047] For example: 2. The first detection board 3 is installed on the metal shielding belt 2, and then the metal shielding belt 2 is installed so that the first detection board 3 is close to or abuts against the kettle body 1. In this embodiment, since the first detection board 3 is installed on the metal shielding belt 2, the first detection board 3 can be easily disassembled and replaced, which is convenient for maintenance; at the same time, the gap between the first detection board 3 and the metal shielding belt 2 becomes smaller, which is conducive to improving the shielding effect and reducing parasitic capacitance and external interference. The first detection board 3 can be installed to the metal shielding belt 2 by gluing.

[0048] In addition, in some implementations of the above embodiments, the first detection board 3 can adopt a common hard substrate or a flexible substrate, and the capacitor electrode is arranged on the side of the substrate facing the kettle body 1. The flexible substrate is conducive to better fitting the curve of the metal shielding belt 2 or the kettle body 1. The hard substrate can be installed in sections to match the curve of the metal shielding belt 2 or the kettle body 1. In actual use, the first detection board 3 can also be connected to the control chip through a wire or a flexible cable. When the liquid level is too high or the foam increases, the control chip can adjust the heating power of the liquid heater to avoid overflow of the beverage in the liquid heater.

[0049] In actual use, different matching relationships between the metal shielding tape 2 and the first detection plate 3 include clearance matching or abutment, etc. Different matching relationships will have different effects on the detection of the first detection plate 3.

[0050] For example: 1. A gap (about 1-2 mm) is left between the metal shielding belt 2 and the first detection plate 3, or a bracket or the like is used to prevent the metal shielding belt 2 from directly contacting the first detection plate 3, thereby achieving a gap fit. The gap fit avoids the metal shielding belt 2 from exerting mechanical pressure on the metal shielding belt 2, reduces the measurement error caused by mechanical deformation, and also leaves room for some installation errors. In specific use, the distance between the metal shielding belt 2 and the outside of the kettle body 1 is greater than the thickness of the first detection plate 3 (and its installation structure), and the sealant 102 may be first coated on the outer wall of the kettle body 1, and the first detection plate 3 and the capacitor electrode are first installed by the sealant 102, and then the metal shielding belt 2 is fixed by the sealant 102. In specific use, it can also be achieved by other methods.

[0051] For example: 2. The metal shielding belt 2 is in contact with the first detection board 3. Since there is no gap, the metal shielding belt 2 has a better effect of shielding the parasitic capacitance of the first detection board 3, and also prevents the first detection board 3 from loosening or falling off. In specific use, the first detection board 3 can be fixed to the metal shielding belt 2 first, and then the metal shielding belt 2 can be installed on the kettle body 1. In specific use, it can also be achieved in other ways.

[0052] In actual use, in addition to the above-mentioned installation method of the metal shielding belt 2, the fixing belt can also be installed by welding, riveting and bolting.

[0053] In actual use, the first detection plate 3 can be arranged on the upper side of the highest water level line of the kettle body 1 near the kettle mouth. In order to detect the liquid level of the beverage when it is below the highest water level line, in some embodiments, a second detection plate is separately arranged on the lower side of the first detection plate 3, and the second detection plate can be installed along the height direction of the kettle body 1 to facilitate the detection of the liquid level of the beverage.

[0054] In some embodiments, the capacitor electrode is used to detect liquid level, including water level detection and foam detection.

[0055] In some embodiments, the first detection board 3 may be coated with a waterproof insulating layer to prevent the capacitor electrode from short-circuiting due to contact with water or metal.

[0056] In some embodiments, the metal shielding tape 2 can be connected to a ground wire in a power source through a wire. The metal shielding tape 2 can also be grounded through a coupler in the liquid heater.

[0057] In addition, it should be noted that the liquid heater of the utility model is not limited to the food processor with integrated motor and cup body disclosed in the embodiment of the utility model, but can also be a soymilk machine with motor mounted on top, a wall-breaking machine with cup body and base separated, and a food processor that can realize automatic pulp discharge and automatic cleaning without hand washing. Moreover, the liquid heater of the utility model can also be applied to heating appliances that can perform pulp boiling operations, rice paste making, etc., such as liquid heaters, health cookers, etc.

[0058] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may be subject to various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A liquid heater, comprising a non-metal kettle body for containing liquid, and a first detection plate arranged on the outer wall of the kettle body, wherein a capacitor electrode is arranged on the first detection plate, and the capacitor electrode is used to detect the liquid level. Features: It comprises a metal shielding belt which surrounds the outer wall of the kettle body and is grounded. The capacitor electrode is located between the metal shielding belt and the outer wall of the kettle body. The width of the metal shielding belt is greater than that of the capacitor electrode.

2. A liquid heater according to claim 1, characterized in that: There are multiple capacitor pole pieces, which are arranged around the outer wall of the kettle body along the metal shielding belt.

3. A liquid heater according to claim 1, characterized in that: A handle and a fastener are also provided on the outer side of the kettle body, and a connecting hole is provided on the metal shielding belt. The fastener passes through the connecting hole and is installed on the handle.

4. A liquid heater according to claim 3, characterized in that: There are multiple capacitor pole pieces, and the multiple capacitor pole pieces are symmetrically arranged on both sides of the fastener.

5. The liquid heater according to claim 1, characterized in that: A gap is left between the metal shielding tape and the first detection plate.

6. A liquid heater according to claim 1, characterized in that: The metal shielding belt is installed on the kettle body through sealant, and the capacitor electrode is located in the sealant.

7. The liquid heater according to claim 1, characterized in that: A bracket is arranged between the metal shielding belt and the outer wall of the kettle body, a mounting groove is arranged on the side of the bracket facing the outer wall of the kettle body, and the capacitor electrode is arranged in the mounting groove.

8. The liquid heater according to claim 1, characterized in that: The capacitor electrode is fixed to the outer wall of the kettle body, and the metal shielding belt is in contact with the first detection plate; or, The capacitor electrode is fixed to the metal shielding belt, and the first detection plate is in contact with the outer wall of the kettle body.

9. The liquid heater according to claim 1, characterized in that: A second detection plate is separately disposed at the lower side of the first detection plate.

10. The liquid heater according to claim 1, characterized in that: The first detection board is made of flexible material.

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