# US 2019/0170562 A1 · Liquid level detection method and liquid level sensor > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2019/0170562 A1 - Document ID: US20190170562A1 - Status: Published application - Kind: A1 - Application number: 16/324,378 - Filed: 2017-01-06 - Published: 2019-06-06 - Earliest claimed: 2016-08-11 - Assignees: Dongguan Zhengyang Electronic Mechanical Co., Ltd. - Applicants: Dongguan Zhengyang Electronic Mechanical Co., Ltd. - Inventors: Yi-Hsin Ku - Web page: https://patentgrep.com/patent/US20190170562A1 ## CPC - G01F 23/72: using magnetically actuated indicating means - G01F 23/74: for sensing changes in level only at discrete points - G01F 25/20: of apparatus for measuring liquid level - G01F: MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME ## Abstract Provided is a liquid level detection method and a liquid level sensor, which relate to the field of liquid level measurement technologies. The liquid level detection method includes that a position of a magnetic field formed by two magnets with same poles disposed facing to each other changes accordingly when a position of a float changes; a plurality of magnetoresistive elements for collecting magnetoresistive signals is disposed equidistantly at a movement range of the float; and two adjacent magnetoresistive elements located between the two magnets detect change of magnetic field intensity and output a linear detection result when the float moves, and a liquid level height value is calculated according to the detection result. ## Claims ### Claim 1 A liquid level detection method, comprising: forming a magnetic field by two magnets with same poles disposed facing to each other; wherein a position of the magnetic field changes accordingly when a position of a float changes; disposing a plurality of magnetoresistive elements equidistantly for collecting magnetoresistive signals at a movement range of the float; and detecting, by two adjacent magnetoresistive elements located between the two magnets, change of a magnetic field intensity and outputting a linear detection result, when the float moves, and calculating, according to the detection result, a liquid level height value. ### Claim 2 (depends on 1) The liquid level detection method according to claim 1, wherein the step of detecting, by the two adjacent magnetoresistive elements located between the two magnets, change of the magnetic field intensity and outputting the linear detection result, when the float moves, and calculating, according to the detection result, the liquid level height value, comprises: denoting an output voltage value of a first magnetoresistive element as V1Initial when the output voltage value is not affected by the magnetic field; denoting a position where the first magnetoresistive element is located between the two magnets during the magnet moves along with the float as a current position, and denoting the output voltage value of the first magnetoresistive element at the time when the first magnetoresistive element is located between the two magnets as V1Current; and calculating a distance H between the first magnetoresistive element and a plane where a designated position on the magnet is located along a movement direction of the float by using a difference between output voltage values V1Current and V1Initial; and obtaining, by adding or subtracting the distance H according to a position of the first magnetoresistive element on an electronic tube, the liquid level height value. ### Claim 3 (depends on 1) The liquid level detection method according to claim 1, wherein the step of detecting, by the two adjacent magnetoresistive elements located between the two magnets, change of the magnetic field intensity and outputting the linear detection result when the float moves, and calculating, according to the detection result, the liquid level height value comprises: denoting an output voltage value of a first magnetoresistive element which is not affected by the magnetic field as V1Initial and an output voltage value of a second magnetoresistive element which is not affected by the magnetic field as V2Initial; denoting a position where the first magnetoresistive element and the second magnetoresistive element are located between the two magnets during the magnet moves along with the float as a current position, and denoting the output voltage value of the first magnetoresistive element at the time when the first magnetoresistive element and the second magnetoresistive element are located between the two magnets as V1Current and the output voltage value of the second magnetoresistive element at the time when the first magnetoresistive element and the second magnetoresistive element are located between the two magnets as V2Current; calculating a distance H between the first magnetoresistive element and a plane where a designated position on the magnet is located along a movement direction of the float by using a ratio of a difference between the output voltage values V1Current and V1Initial of the first magnetoresistive element and the difference between the output voltage values V2Current and V2Initial of the second magnetoresistive element; and obtaining, by adding or subtracting the distance H according to a position of the first magnetoresistive element on an electronic tube, the liquid level height value. ### Claim 4 (depends on 3) The liquid level detection method according to claim 3, wherein when a distance between the two adjacent magnetoresistive elements is L, a length of the magnet is 2L and a distance between the two magnets is 2L, an output of the magnetic field intensity detected by the first magnetoresistive element is in a shape of cosine curve and an output of the magnetic field intensity detected by the second magnetoresistive element is in a shape of sine curve, and the phase difference between the output of the first magnetoresistive element and the output of the second magnetoresistive element is 90°; the distance H is calculated according to a formula below: H = arctan  ( V 2  Current - V 2  Initial V 1  Current - V 1  Initial ) × 180  ° π × L 90  ° wherein V2Current is a current output voltage value of the second magnetoresistive element, V2Initial is an initial output voltage value of the second magnetoresistive element, V1Current is the current output voltage value of the first magnetoresistive element and V1Initial is the initial output voltage value of the first magnetoresistive element; and the first magnetoresistive element and the second magnetoresistive element are the two adjacent magnetoresistive elements within the magnetic field, and the first magnetoresistive element is located above the second magnetoresistive element. ### Claim 5 A liquid level sensor for implementing a liquid level detection method, comprising an electronic tube, a plurality of magnetoresistive elements, a float and two magnets; wherein the plurality of magnetoresistive elements are longitudinally and sequentially disposed in the electronic tube; the float rotatably sleeves on the electronic tube; the two magnets are disposed on the float, and same poles of the two magnets are disposed facing to the plurality of magnetoresistive elements; and the plurality of magnetoresistive elements are equidistantly distributed, a distance between two adjacent magnetoresistive elements is L, and a length of each of the magnets is 2L; and wherein the liquid level detection method comprises forming a magnetic field by the two magnets with same poles disposed facing to each other; wherein a position of the magnetic field changes accordingly when a position of the float changes; disposing the plurality of magnetoresistive elements equidistantly for collecting magnetoresistive signals at a movement range of the float; and detecting, by two adjacent magnetoresistive elements located between the two magnets, change of a magnetic field intensity and outputting a linear detection result, when the float moves, and calculating, according to the detection result, a liquid level height value. ### Claim 6 (depends on 5) The liquid level sensor according to claim 5, wherein a distance between the two magnets is 2L. ### Claim 7 (depends on 5) The liquid level sensor according to claim 5, wherein a plurality of adjacent magnetoresistive elements are connected to a differential multiplexer switch; a plurality of differential multiplexer switches are connected to a serial-to-parallel switch, the serial-to-parallel switch is connected to an impedance transformation circuit and a differential amplifier circuit, the differential amplifier circuit is connected to a single-chip microcomputer processing system; and the single-chip microcomputer processing system is connected to the serial-to-parallel switch and an output terminal respectively to implement data collection, data processing and calculation result output. ### Claim 8 (depends on 7) The liquid level sensor according to claim 7, further comprising a calibration device, which is configured to be connected to the single-chip microcomputer processing system by a digital interface, and record at least one of an initial output voltage value of the magnetoresistive element and an assembling error value of the liquid level sensor. ### Claim 9 (depends on 5) The liquid level sensor according to claim 5, wherein the step of detecting, by the two adjacent magnetoresistive elements located between the two magnets, change of the magnetic field intensity and outputting the linear detection result, when the float moves, and calculating, according to the detection result, the liquid level height value, comprises: denoting an output voltage value of a first magnetoresistive element as V1Initial when the output voltage value is not affected by the magnetic field; denoting a position where the first magnetoresistive element is located between the two magnets during the magnet moves along with the float as a current position, and denoting the output voltage value of the first magnetoresistive element at the time when the first magnetoresistive element is located between the two magnets as V1Current; calculating a distance H between the first magnetoresistive element and a plane where a designated position on the magnet is located along a movement direction of the float by using a difference between output voltage values V1Current and V1Initial; and obtaining, by adding or subtracting the distance H according to a position of the first magnetoresistive element on an electronic tube, the liquid level height value. ### Claim 10 (depends on 5) The liquid level sensor according to claim 5, wherein the step of detecting, by the two adjacent magnetoresistive elements located between the two magnets, change of the magnetic field intensity and outputting the linear detection result when the float moves, and calculating, according to the detection result, the liquid level height value comprises: denoting an output voltage value of a first magnetoresistive element which is not affected by the magnetic field as V1Initial and an output voltage value of a second magnetoresistive element which is not affected by the magnetic field as V2Initial; denoting a position where the first magnetoresistive element and the second magnetoresistive element are located between the two magnets during the magnet moves along with the float as a current position, and denoting the output voltage value of the first magnetoresistive element at the time when the first magnetoresistive element and the second magnetoresistive element are located between the two magnets as V1Current and the output voltage value of the second magnetoresistive element at the time when the first magnetoresistive element and the second magnetoresistive element are located between the two magnets as V2Current; calculating a distance H between the first magnetoresistive element and a plane where a designated position on the magnet is located along a movement direction of the float by using a ratio of a difference between the output voltage values V1Current and V1Initial of the first magnetoresistive element and the difference between the output voltage values V2Current and V2Initial of the second magnetoresistive element; and obtaining, by adding or subtracting the distance H according to a position of the first magnetoresistive element on an electronic tube, the liquid level height value. ### Claim 11 (depends on 10) The liquid level sensor according to claim 10, wherein a distance between the two magnets is 2L, an output of the magnetic field intensity detected by the first magnetoresistive element is in a shape of cosine curve and an output of the magnetic field intensity detected by the second magnetoresistive element is in a shape of sine curve, and the phase difference between the output of the first magnetoresistive element and the output of the second magnetoresistive element is 90°; the distance H is calculated according to a formula below: H = arctan  ( V 2  Current - V 2  Initial V 1   Current - V 1   Initial ) × 180  ° π × L 90  ° wherein V2Current is a current output voltage value of the second magnetoresistive element, V2Initial is an initial output voltage value of the second magnetoresistive element, V1Current is the current output voltage value of the first magnetoresistive element and V1Initial is the initial output voltage value of the first magnetoresistive element; and the first magnetoresistive element and the second magnetoresistive element are the two adjacent magnetoresistive elements within the magnetic field, and the first magnetoresistive element is located above the second magnetoresistive element. ### Claim 12 (depends on 6) The liquid level sensor according to claim 6, wherein a plurality of adjacent magnetoresistive elements are connected to a differential multiplexer switch; a plurality of differential multiplexer switches are connected to a serial-to-parallel switch, the serial-to-parallel switch is connected to an impedance transformation circuit and a differential amplifier circuit, the differential amplifier circuit is connected to a single-chip microcomputer processing system; and the single-chip microcomputer processing system is connected to the serial-to-parallel switch and an output terminal respectively to implement data collection, data processing and calculation result output.