CN111206376A - Liquid level detection device and method and washing machine - Google Patents
Liquid level detection device and method and washing machine Download PDFInfo
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Abstract
The invention discloses a liquid level detection device, and belongs to the technical field of liquid level detection. The device includes: the measuring device comprises a reference capacitor and a measuring capacitor, wherein the reference capacitor and the measuring capacitor are arranged on the side wall of the container, the reference capacitor comprises two metal conductive strips, and the measuring capacitor comprises two metal conductive strips; the detection circuit is respectively connected to the reference capacitor and the measuring capacitor and used for measuring capacitance values of the reference capacitor and the measuring capacitor; and the control circuit determines the liquid level height according to the ratio of the measured capacitance to the reference capacitance. By adopting the optional embodiment, the liquid level height in the container can be accurately measured, and the service life of the liquid level detection device can be prolonged. The invention also discloses a liquid level detection method and a washing machine.
Description
Technical Field
The invention relates to the technical field of liquid level detection, in particular to a liquid level detection device and method and a washing machine.
Background
Currently, the detection of the detergent level in a detergent box is mainly realized by arranging a float switch or a probe.
According to the scheme of detecting the liquid level by the float switch, because the detergent is viscous, the condition that the float switch is stuck on the guide post by the detergent and does not change along with the liquid level often occurs, so that misjudgment is caused in liquid level detection; through the scheme of probe detection liquid level, the probe surface can form one deck oxide film in the use, because the non-conductivity of oxide film, the probe can become invalid to lead to whole detection circuitry can't normally work, washing machine or other device that need detergent liquid level numerical value can't correctly judge the liquid level of detergent.
The water bucket of washing machine is used for holding the washing water, and the level detection to the washing water at present mainly adopts level sensor to realize, and level sensor's is with high costs, and the wiring is complicated, need set up special level sensor wiring route, and moreover, level sensor's level measurement precision is lower.
Disclosure of Invention
The embodiment of the invention provides a liquid level detection device and method and a washing machine. The following presents a simplified summary in order to provide a basic understanding of some aspects of the disclosed embodiments. This summary is not an extensive overview and is intended to neither identify key/critical elements nor delineate the scope of such embodiments. Its sole purpose is to present some concepts in a simplified form as a prelude to the more detailed description that is presented later.
According to a first aspect of embodiments of the present invention, there is provided a liquid level detection apparatus for detecting a level of a liquid inside a container.
In some optional embodiments, the apparatus comprises: the measuring device comprises a reference capacitor and a measuring capacitor, wherein the reference capacitor and the measuring capacitor are arranged on the side wall of the container, the reference capacitor comprises two metal conductive strips, and the measuring capacitor comprises two metal conductive strips; the detection circuit is respectively connected to the reference capacitor and the measuring capacitor and used for measuring capacitance values of the reference capacitor and the measuring capacitor; and the control circuit determines the liquid level height according to the ratio of the measured capacitance to the reference capacitance. The capacitance values of the reference capacitor and the measurement capacitor are determined by the metal conductive strips below the liquid level, and the dielectric constants of the reference capacitor and the measurement capacitor are the same, so that the ratio of the measurement capacitor to the reference capacitor is independent of the dielectric constant and is only related to the distance between the two metal conductive strips and the facing area of the part below the liquid level of the two metal conductive strips, after the parameters are installed and fixed, the metal conductive strips of the reference capacitor are lower than the liquid level height, and only the height of the part below the liquid level of the metal conductive strips of the measurement capacitor is a variable. By adopting the optional embodiment, the liquid level height is determined according to the ratio of the measured capacitance to the reference capacitance, the measurement precision is high, the service life is long, the phenomenon that a floater switch is stuck on a guide post by detergent to cause misjudgment is avoided, and the phenomenon that the liquid level is detected by a probe, and the surface of the probe loses efficacy due to the generation of an oxide film is also avoided; and the measured capacitance is compared with the reference capacitance and then is irrelevant to the dielectric constant, so that the liquid level sensor is suitable for liquid level detection of various liquids, and the measurement precision is high.
Optionally, the height of the two metal conductive strips of the reference capacitor is lower than the lowest detection level, and the height of the two metal conductive strips of the measurement capacitor is lower than the highest detection level and higher than the lowest detection level. By adopting the optional embodiment, when the liquid level is higher than the metal conductive belt of the measuring capacitor, the liquid level cannot be measured due to the unchanged capacitance value of the measuring capacitor; when the liquid level is lower than the metal conductive belt of the measuring capacitor, the capacitance value of the measuring capacitor changes, and the liquid level starts to be monitored; when the liquid level is lower than the lowest detection liquid level, the low liquid level is measured in time.
Optionally, the height of the two metal conductive strips of the reference capacitor is lower than the lowest detection level, and the height of the two metal conductive strips of the measurement capacitor is higher than the highest detection level. With this alternative embodiment, the reference capacitance C is due to the fact that the height of the two metallic conductive strips of the reference capacitance is lower than the minimum detection levelrefThe capacitance value of the measuring capacitor C can not change along with the liquid level change, and the measuring capacitor C is measured because the height of the two metal conductive belts of the measuring capacitor C is higher than the highest detection liquid level1Different capacitance values can be presented along with the liquid level change, so that the liquid level change process only measures the height of the part below the liquid level of the capacitive metal conductive belt as a variable, and the liquid level height in the non-conductor container can be accurately measured.
Optionally, the container is a non-conductive container, and the reference capacitance and the measurement capacitance are disposed on an outer sidewall of the container. With this alternative embodiment, the service life of the liquid level detection device can be extended because the reference capacitance and the measurement capacitance are not in contact with the liquid.
Optionally, the distance between the two metal conductive strips of the reference capacitance is equal to the distance between the two metal conductive strips of the measurement capacitance. With this alternative embodiment, the liquid level height calculation step is further simplified.
Optionally, the two metal conductive strips of the reference capacitor are disposed adjacently, and the two metal conductive strips of the measurement capacitor are also disposed adjacently. By adopting the optional embodiment, the dielectric constants of the reference capacitor and the measurement capacitor can be ensured to be a more significant value, and the accuracy of liquid level measurement is ensured.
According to a second aspect of the embodiments of the present invention, there is provided a liquid level detection method based on the device of any one of the previous alternative embodiments.
In some alternative embodiments, the method comprises the steps of:
step 11, obtaining capacitance values of a measurement capacitor and a reference capacitor;
and step 12, obtaining the liquid level height according to the ratio of the capacitance value of the measurement capacitor to the capacitance value of the reference capacitor.
By adopting the optional embodiment, the liquid level height is determined according to the ratio of the measurement capacitor to the reference capacitor, the measurement precision is high, the service life is long, the phenomenon that the float switch is stuck on the guide post by detergent to cause misjudgment is avoided, the scheme that the liquid level is detected by the probe is also avoided, and the surface of the probe loses efficacy due to the generation of an oxide film.
Optionally, the step of obtaining the liquid level height according to the ratio of the capacitance value of the measurement capacitor to the capacitance value of the reference capacitor includes the following steps:
the reference capacitance is represented as:
wherein, CrefFor reference capacitance,. epsilon.is the dielectric constant, SrefFor reference to the facing area of the two metal conductive strips of the capacitor, drefIs prepared from radix GinsengThe distance between two metal conductive strips of the capacitor is considered;
the measured capacitance is expressed as:
wherein, C1For measuring capacitance,. epsilon.is the dielectric constant, S1For measuring the area of the capacitor facing the parts below the level of the two metal conducting strips, d1Measuring the distance between two metal conductive strips of the capacitor;
first, the ratio of the measured capacitance to the reference capacitance is calculated as:
then, the facing area S of two metal conductive strips of the reference capacitorrefIt is known to measure the distance d between two metal conducting strips of a capacitor1The distance d between two metal conductive strips of the reference capacitor is knownrefAnd when the width of the two metal conductive strips of the measuring capacitor is known, calculating to obtain the height of the part of the measuring capacitor below the liquid level of the two metal conductive strips.
With this alternative embodiment, the capacitance values of the reference capacitance and the measurement capacitance are determined by the metal conductive strips below the liquid level, and the dielectric constants of the reference capacitance and the measurement capacitance are the same, so that the ratio of the measurement capacitance to the reference capacitance is independent of the dielectric constant and is only related to the distance between the two metal conductive strips and the facing area of the part below the liquid level of the two metal conductive strips.
Optionally, the method further comprises the steps of: when the widths of the two metal conductive strips of the measuring capacitor are equal to the widths of the two metal conductive strips of the reference capacitor, and the distance d between the two metal conductive strips of the measuring capacitor is measured1Equal to two metal conductive strips of reference capacitorA distance d betweenrefThen, the ratio of the measured capacitance to the reference capacitance is:
wherein HrefHeight of two metal conductive strips of the reference capacitor H1And measuring the height of the part of the capacitor below the liquid level of the two metal conductive strips.
With this alternative embodiment, the liquid level height calculation step is further simplified.
According to a third aspect of embodiments of the present invention, there is provided a washing machine comprising a container for storing detergent, and further comprising the liquid level detection apparatus according to any one of the previous alternative embodiments.
According to a fourth aspect of embodiments of the present invention, there is provided a washing machine including a tub for holding washing water, and further including the liquid level detection apparatus of any one of the foregoing alternative embodiments.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and together with the description, serve to explain the principles of the invention.
FIG. 1 is a schematic view showing a structure of a liquid level detecting device according to an exemplary embodiment;
FIG. 2 is a flow chart illustrating a method of liquid level detection according to an exemplary embodiment.
Detailed Description
The following description and the drawings sufficiently illustrate specific embodiments of the invention to enable those skilled in the art to practice them. Other embodiments may incorporate structural, logical, electrical, process, and other changes. The examples merely typify possible variations. Individual components and functions are optional unless explicitly required, and the sequence of operations may vary. Portions and features of some embodiments may be included in or substituted for those of others. The scope of embodiments of the invention encompasses the full ambit of the claims, as well as all available equivalents of the claims. Embodiments may be referred to herein, individually or collectively, by the term "invention" merely for convenience and without intending to voluntarily limit the scope of this application to any single invention or inventive concept if more than one is in fact disclosed. Herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other like elements in a process, method or apparatus that comprises the element. The embodiments are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other. As for the methods, products and the like disclosed by the embodiments, the description is simple because the methods correspond to the method parts disclosed by the embodiments, and the related parts can be referred to the method parts for description.
Fig. 1 shows an alternative embodiment of the liquid level detection device.
In this alternative embodiment, the device for detecting the level of a liquid inside a container comprises: a reference capacitor 20 and a measurement capacitor 30 arranged on the side wall of the container 10, wherein the reference capacitor comprises two metal conductive strips, and the measurement capacitor comprises two metal conductive strips; the detection circuit is respectively connected to the reference capacitor and the measuring capacitor and used for measuring capacitance values of the reference capacitor and the measuring capacitor; and the control circuit determines the liquid level height according to the ratio of the measured capacitance to the reference capacitance.
Two metal conductive strips form two stages of the capacitor, the liquid or air in the middle is the medium of the capacitor, and the influence of the air on the dielectric constant is small, so that the dielectric constants of the measured capacitor and the reference capacitor are mainly determined by the part below the liquid level of the metal conductive strips. The dielectric constants of the reference capacitor and the measurement capacitor are the same, so that the ratio of the measurement capacitor to the reference capacitor is irrelevant to the dielectric constant and is only relevant to the distance between the two metal conductive strips and the facing area of the part below the liquid level of the two metal conductive strips. By adopting the optional embodiment, the liquid level height is determined according to the ratio of the measured capacitance to the reference capacitance, the measurement precision is high, the service life is long, the phenomenon that a floater switch is stuck on a guide post by detergent to cause misjudgment is avoided, and the phenomenon that the liquid level is detected by a probe, and the surface of the probe loses efficacy due to the generation of an oxide film is also avoided; and the measured capacitance is compared with the reference capacitance and then is irrelevant to the dielectric constant, so that the liquid level sensor is suitable for liquid level detection of various liquids, and the measurement precision is high.
Optionally, the vessel comprises a maximum detection level and a minimum detection level, the detergent level being between the maximum detection level and the minimum detection level after addition of detergent.
Optionally, the height of the two metal conductive strips of the reference capacitor is lower than the lowest detection level, and the height of the two metal conductive strips of the measurement capacitor is lower than the highest detection level and higher than the lowest detection level. By adopting the optional embodiment, when the liquid level is higher than the metal conductive belt of the measuring capacitor, the liquid level cannot be measured due to the unchanged capacitance value of the measuring capacitor; when the liquid level is lower than the metal conductive belt of the measuring capacitor, the capacitance value of the measuring capacitor changes, and the liquid level starts to be monitored; when the liquid level is lower than the lowest detection liquid level, the low liquid level is measured in time.
For example, when the liquid level is higher than the measuring capacitance metal conductive belt, a liquid level full signal can be output, and the liquid level height does not need to be monitored in real time; when the liquid level is lower than the metal conductive belt of the measuring capacitor, the liquid level starts to be monitored in real time, and the current liquid level can be displayed in real time; when the liquid level is lower than the lowest detection liquid level, a liquid shortage indication is sent out in time.
The liquid level below the measuring capacitance metal conductive band is lower than the upper edge of the measuring capacitance metal conductive band.
Optionally, the height of the two metal conductive strips of the reference capacitor is lower than the lowest detection level, and the height of the two metal conductive strips of the measurement capacitor is higher than the highest detection level. With this alternative embodiment, the reference capacitance C is due to the fact that the height of the two metallic conductive strips of the reference capacitance is lower than the minimum detection levelrefThe capacitance value of the measuring capacitor C can not change along with the liquid level change, and the measuring capacitor C is measured because the height of the two metal conductive belts of the measuring capacitor C is higher than the highest detection liquid level1Different capacitance values can be presented along with the liquid level change, so that the liquid level change process only measures the height of the part below the liquid level of the capacitive metal conductive belt as a variable, and the liquid level height in the non-conductor container can be accurately measured.
Optionally, the container is a non-conductive container.
Optionally, the reference capacitance and the measurement capacitance are disposed on an outer sidewall of the non-conductive container. By adopting the alternative embodiment, the corrosion of the detergent to the reference capacitor and the measuring capacitor can be reduced, the precision of the liquid level detection circuit is improved, and the service life of the liquid level detection circuit is prolonged.
Optionally, the reference capacitance and the measurement capacitance are disposed on an inner sidewall of the non-conductive container. With this alternative embodiment, the dielectric constant of the portion below the measured capacitance level is more significant than the dielectric constant of the portion above the level, which may make the measurement of the measurement data of the portion below the capacitance level more accurate.
Optionally, the container is a conductor container, and the reference capacitor and the measurement capacitor are disposed inside the conductor container and are not in contact with an inner side wall of the conductor container.
Optionally, the distance between the two metal conductive strips of the reference capacitance is equal to the distance between the two metal conductive strips of the measurement capacitance. With this alternative embodiment, the liquid level height calculation step is further simplified.
Optionally, the two metal conductive strips of the reference capacitor are disposed adjacently, and the two metal conductive strips of the measurement capacitor are also disposed adjacently. By adopting the optional embodiment, the dielectric constants of the reference capacitor and the measurement capacitor can be ensured to be a more significant value, and the accuracy of liquid level measurement is ensured.
Optionally, the two metal conductive strips of the reference capacitor are arranged in parallel on one side of the non-conductor container, and the two metal conductive strips of the measurement capacitor are arranged in parallel on the other side of the non-conductor container.
Optionally, the detection circuit is an existing capacitance value measurement circuit, and outputs a capacitance value of the reference capacitor and a capacitance value of the measurement capacitor.
Optionally, the control circuit is configured to calculate a ratio of a capacitance value of the measurement capacitance and a capacitance value of the reference capacitance, wherein:
the reference capacitance is represented as:
wherein, CrefFor reference capacitance,. epsilon.is the dielectric constant, SrefFor reference to the facing area of the two metal conductive strips of the capacitor, drefThe distance between the two metal conductive strips of the reference capacitor is taken as the reference capacitor;
the measured capacitance is expressed as:
wherein, C1For measuring capacitance,. epsilon.is the dielectric constant, S1For measuring the area of the capacitor facing the parts below the level of the two metal conducting strips, d1For measuring the distance between two metal conducting strips of a capacitor；
First, the ratio of the measured capacitance to the reference capacitance is calculated as:
then, the facing area S of two metal conductive strips of the reference capacitorrefIt is known to measure the distance d between two metal conducting strips of a capacitor1The distance d between two metal conductive strips of the reference capacitor is knownrefAnd when the width of the two metal conductive strips of the measuring capacitor is known, calculating to obtain the height of the part of the measuring capacitor below the liquid level of the two metal conductive strips.
FIG. 2 illustrates an alternative embodiment of a liquid level detection method.
In this alternative embodiment, the method is based on the liquid level detection device described above for detecting the level of a liquid inside a non-conductive container, the method comprising the steps of:
step 11, obtaining capacitance values of a measurement capacitor and a reference capacitor;
and step 12, obtaining the liquid level height according to the ratio of the capacitance value of the measurement capacitor to the capacitance value of the reference capacitor.
By adopting the optional embodiment, the liquid level height is determined according to the ratio of the measurement capacitor to the reference capacitor, the measurement precision is high, the service life is long, the phenomenon that the float switch is stuck on the guide post by detergent to cause misjudgment is avoided, the scheme that the liquid level is detected by the probe is also avoided, and the surface of the probe loses efficacy due to the generation of an oxide film.
Optionally, the step of obtaining the liquid level height according to a ratio of the capacitance value of the measurement capacitor to the capacitance value of the reference capacitor further includes:
the reference capacitance is represented as:
wherein, CrefFor reference capacitance,. epsilon.is the dielectric constant, SrefArea directly opposite to two metal conductive bands of reference capacitor，drefThe distance between the two metal conductive strips of the reference capacitor is taken as the reference capacitor;
the measured capacitance is expressed as:
wherein, C1For measuring capacitance,. epsilon.is the dielectric constant, S1For measuring the area of the capacitor facing the parts below the level of the two metal conducting strips, d1Measuring the distance between two metal conductive strips of the capacitor;
first, the ratio of the measured capacitance to the reference capacitance is calculated as:
then, the facing area S of two metal conductive strips of the reference capacitorrefIt is known to measure the distance d between two metal conducting strips of a capacitor1The distance d between two metal conductive strips of the reference capacitor is knownrefAnd when the width of the two metal conductive strips of the measuring capacitor is known, calculating to obtain the height of the part of the measuring capacitor below the liquid level of the two metal conductive strips.
With this alternative embodiment, the capacitance values of the reference capacitance and the measurement capacitance are determined by the metal conductive strips below the liquid level, and the dielectric constants of the reference capacitance and the measurement capacitance are the same, so that the ratio of the measurement capacitance to the reference capacitance is independent of the dielectric constant and is only related to the distance between the two metal conductive strips and the facing area of the part below the liquid level of the two metal conductive strips.
Optionally, the method further comprises the steps of:
when the width of the two metal conductive strips of the measuring capacitor is equal to that of the two metal conductive strips of the reference capacitor, and the distance between the two metal conductive strips of the measuring capacitor is measuredDistance d of1Equal to the distance d between two metal conductive strips of the reference capacitorrefThen, the ratio of the measured capacitance to the reference capacitance is:
wherein HrefHeight of two metal conductive strips of the reference capacitor H1And measuring the height of the part of the capacitor below the liquid level of the two metal conductive strips.
With this alternative embodiment, the liquid level height calculation step is further simplified.
In some optional embodiments, a washing machine is proposed, wherein the washing machine comprises a container for storing detergent, and further comprises the liquid level detection device described above, wherein the liquid level detection device is used for detecting the liquid level of the detergent in the container.
In some optional embodiments, a laundry machine is proposed, wherein the laundry machine comprises a tub for holding wash water, and further comprises the liquid level detection device as described above for detecting the level of the wash water in the tub.
In an exemplary embodiment, there is also provided a computer device comprising a memory, a processor and a program stored on the memory and executable by the processor, the processor when executing the program performing the liquid level detection method as described above.
In an exemplary embodiment, a non-transitory computer readable storage medium is also provided that includes instructions, such as a memory, that are executable by a processor to perform the fluid level detection method described above. The non-transitory computer readable storage medium may be a Read Only Memory (ROM), a Random Access Memory (RAM), a magnetic tape, an optical storage device, and the like.
Those of skill in the art would appreciate that the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware or combinations of computer software and electronic hardware. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the implementation. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present invention. It is clear to those skilled in the art that, for convenience and brevity of description, the specific working processes of the above-described systems, apparatuses and units may refer to the corresponding processes in the foregoing method embodiments, and are not described herein again.
In the embodiments disclosed herein, it should be understood that the disclosed methods, articles of manufacture (including but not limited to devices, apparatuses, etc.) may be implemented in other ways. For example, the above-described apparatus embodiments are merely illustrative, and for example, the division of the units is only one logical division, and other divisions may be realized in practice, for example, a plurality of units or components may be combined or integrated into another system, or some features may be omitted, or not executed. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection through some interfaces, devices or units, and may be in an electrical, mechanical or other form. The units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment. In addition, functional units in the embodiments of the present invention may be integrated into one processing unit, or each unit may exist alone physically, or two or more units are integrated into one unit.
It should be understood that the flowchart and block diagrams in the figures illustrate the architecture, functionality, and operation of possible implementations of systems, methods and computer program products according to various embodiments of the present invention. In this regard, each block in the flowchart or block diagrams may represent a module, segment, or portion of code, which comprises one or more executable instructions for implementing the specified logical function(s). It should also be noted that, in some alternative implementations, the functions noted in the block may occur out of the order noted in the figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. It will also be noted that each block of the block diagrams and/or flowchart illustration, and combinations of blocks in the block diagrams and/or flowchart illustration, can be implemented by special purpose hardware-based systems which perform the specified functions or acts, or combinations of special purpose hardware and computer instructions. The present invention is not limited to the procedures and structures that have been described above and shown in the drawings, and various modifications and changes may be made without departing from the scope thereof. The scope of the invention is limited only by the appended claims.
Claims (10)
1. A liquid level detection device for detecting the liquid level of liquid inside a container, comprising:
the measuring device comprises a reference capacitor and a measuring capacitor, wherein the reference capacitor and the measuring capacitor are arranged on the side wall of the container, the reference capacitor comprises two metal conductive strips, and the measuring capacitor comprises two metal conductive strips;
the detection circuit is respectively connected to the reference capacitor and the measuring capacitor and used for measuring capacitance values of the reference capacitor and the measuring capacitor;
and the control circuit determines the liquid level height according to the ratio of the measured capacitance to the reference capacitance.
2. The apparatus of claim 1, wherein the height of the two metallic conductive strips of the reference capacitance is below a minimum detection level and the height of the two metallic conductive strips of the measurement capacitance is below a maximum detection level and above a minimum detection level.
3. The apparatus of claim 1, wherein the reference capacitance has two metallic conductive strips having a height below a lowest detection level and the measurement capacitance has two metallic conductive strips having a height above a highest detection level.
4. The apparatus of claim 1, wherein the container is a non-conductive container, and the reference capacitance and the measurement capacitance are disposed on an exterior sidewall of the non-conductive container.
5. The apparatus of claim 1, wherein the container is a conductor container, and the reference capacitance and the measurement capacitance are disposed inside the conductor container and are not in contact with an inner sidewall of the conductor container.
6. A method for detecting the liquid level based on the device of any one of claims 1 to 5, comprising the following steps:
acquiring capacitance values of a measurement capacitor and a reference capacitor;
and obtaining the liquid level height according to the ratio of the capacitance value of the measurement capacitor to the capacitance value of the reference capacitor.
7. The method of claim 6, wherein the step of obtaining the liquid level height from the ratio of the capacitance of the measured capacitance and the capacitance of the reference capacitance comprises the steps of:
the reference capacitance is represented as:
wherein, CrefFor reference capacitance,. epsilon.is the dielectric constant, SrefFor reference to the facing area of the two metal conductive strips of the capacitor, drefThe distance between the two metal conductive strips of the reference capacitor is taken as the reference capacitor;
the measured capacitance is expressed as:
wherein, C1For measuring capacitance,. epsilon.is the dielectric constant, S1For measuring the area of the capacitor facing the parts below the level of the two metal conducting strips, d1Measuring the distance between two metal conductive strips of the capacitor;
first, the ratio of the measured capacitance to the reference capacitance is calculated as:
then, the facing area S of two metal conductive strips of the reference capacitorrefIt is known to measure the distance d between two metal conducting strips of a capacitor1The distance d between two metal conductive strips of the reference capacitor is knownrefAnd when the width of the two metal conductive strips of the measuring capacitor is known, calculating to obtain the height of the part of the measuring capacitor below the liquid level of the two metal conductive strips.
8. The method of claim 7, further comprising the steps of:
when the widths of the two metal conductive strips of the measuring capacitor are equal to the widths of the two metal conductive strips of the reference capacitor, and the distance d between the two metal conductive strips of the measuring capacitor is measured1Equal to the distance d between two metal conductive strips of the reference capacitorrefThen, the ratio of the measured capacitance to the reference capacitance is:
wherein HrefHeight of two metal conductive strips of the reference capacitor H1And measuring the height of the part of the capacitor below the liquid level of the two metal conductive strips.
9. A washing machine comprising a container for storing detergent, characterized by further comprising a level detection device as claimed in any one of claims 1 to 5.
10. A washing machine comprising a tub for containing wash water, characterized by further comprising a liquid level detection apparatus as claimed in any one of claims 1 to 5.
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| CN113670408A (en) * | 2021-09-14 | 2021-11-19 | 珠海格力电器股份有限公司 | Dish washing machine liquid level detection method and device and dish washing machine |
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| CN102829841A (en) * | 2012-07-30 | 2012-12-19 | 新会康宇测控仪器仪表工程有限公司 | Capacitance liquid level transmitter |
| CN103266445A (en) * | 2013-05-07 | 2013-08-28 | 海尔集团公司 | Centrifugal washing method and washing machine |
| CN205024472U (en) * | 2015-09-18 | 2016-02-10 | 南京创维家用电器有限公司 | Washing machine , detergent storage device and detergent liquid level multistage detection device |
| CN205861162U (en) * | 2016-06-06 | 2017-01-04 | 佛山市顺德区美的电热电器制造有限公司 | Condensate tank of dehumidifier, water tank and water treatment facilities |
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