Patent Publication Number: US-2023160735-A1

Title: Capacitive liquid level sensor

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit and priority of CN-202020746318.5, filed May 8, 2020. The entire disclosure of the above application is incorporated herein by reference. 
     FIELD 
     The present disclosure relates to the sensor field, and particularly to a liquid level sensor. 
     BACKGROUND 
     This section provides background information related to the present disclosure which is not necessarily prior art. 
     In the prior art, there are several methods for measuring the amount of liquid. The device for measuring the amount of non-conductive liquids such as oil can use an electrostatic capacitive sensor. The sensor is a device that detects the presence and amount of liquid through the following principles: Insulating liquid enters between the electrodes intervening the space, and the electro-static capacitance changes between the electrodes. For example, the electrodes are arranged in a barrel-shaped electrically insulating frame, or one electrode is configured in a barrel shape, and the amount of liquid in the container is measured based on the electrostatic capacitance between the electrodes that changes due to the liquid entering and leaving the barrel. There is another method using a flat capacitive sensor.  FIG.  1    is a schematic diagram of a liquid level sensor in prior art. As shown in  FIG.  1   , a liquid level sensor comprises a conductive rod  6 , a metal cover plate  4 , a spacer plate  3 , a soldering lug  9 , and an electrode plate.  7 . In this way, the connection stability is relatively poor, which affects the accuracy and performance of the sensor. 
     SUMMARY 
     This section provides a general summary of the disclosure, and is not a comprehensive disclosure of its full scope or all of its features. 
     The objective of the present invention lies in providing a liquid level sensor so as to solve the above problem. 
     According to one aspect of the disclosure, the liquid level sensor includes a metal cover plate, a conductive pin passing through the metal cover plate, a plurality of electrode plates, and a plurality of support plates supporting the plurality of electrode plates respectively, so that a fixed interval or distance is maintained between the plurality of electrode plates. Each electrode plate of the plurality of electrode plates has a planar portion and a wing portion that extends outwardly from the planar portion of the electrode plate. The wing portion is attached or connected to the conductive pin. 
     Preferably, the wing portion includes a bent portion or bent part and a conductive portion or conductive part. 
     Preferably, the wing portion is located in the middle of the electrode plates. Alternatively, the wing portion is located at the first end of each electrode plate of the plurality of electrode plates, and the distance between the first end and the metal cover plate is less than the distance between the second end of each electrode plate and the metal cover plate. 
     Preferably, the conductive portion is connected to the conductive pin. 
     Preferably, the first surface of the conductive portion is connected to the conductive pin. Alternatively, the second surface of the conductive portion is connected to the conductive pin. 
     Preferably, one support plate of the plurality of support plates is provided at the first end of the electrode plate, and the other support plate of the plurality of support plates is provided at the second end. Alternatively, one support plate of the plurality of support plates is provided at the second end portion, and the other support plate of the plurality of support plates is provided between the wing portion and the second end portion. 
     Preferably, the plurality of electrode plates are arranged in parallel. 
     Preferably, one or more convex parts are provided on the conductive portion. 
     Through the above technical solutions, a liquid level sensor is disclosed as including a metal cover plate, a conductive pin that passes through the metal cover plate, multiple electrode plates, multiple support plates respectively supporting the plurality of electrode plates so that a fixed interval (i.e., a gap or distance) is maintained between the plurality of electrode plates. Further, each electrode plate of the plurality of electrode plates has a wing portion that extends outwardly from a planar portion of each electrode plate. A conductive pin is attached to each wing portion such as by welding. The wing portion and the electrode plate are integrally formed, and the wing portion is connected to the conductive pin, which improves the stability of the connection between the electrode plate and the conductive pin and improves the working stability of the liquid level sensor. 
     According to another aspect of the disclosure, a liquid level sensor can include a metal cover having a cap-shaped body member with a generally flat top surface including at least one aperture, a peripheral side wall extending from the top surface and including a flanged portion at a distal perimeter of the side wall. A plurality of conductive pins can extend through the at least one aperture in the top surface of the body member and from a first side of the metal cover to a second side of the metal cover. A sealing glass can be disposed between each of the plurality of pins and the at least one aperture to hermetically seal the pins to the body member and electrically isolate the pins from the body member and one another. A plurality of generally rectangular-shaped electrically-conductive electrode plates extending from the second side of the cover can be included with each of the electrode plates having a planar portion. A plurality of electrically-insulating support plates can support the plurality of electrode plates. 
     The electrode plates can be positioned in an adjacent relationship to one another such that the planar portions of respective adjacent electrode plates are generally parallel to one another and separated by a predetermined gap. 
     Additionally, each electrode plate of the plurality of electrode plates can include an integrally-formed wing portion that extends laterally outward from the planar portion of the electrode plate. Each wing portion can have a bent portion and an attachment portion. The attachment portion can be laterally spaced or offset from the planar portion of the electrode plate. Each of the conductive pins of the plurality of conductive pins can be attached to the attachment portion of the wing portion of a corresponding electrode plate of the plurality of electrode plates. 
     In a further aspect of the disclosure, the planar portions of each of the plurality of electrode plates can have a first thickness and the wing portions of each of the plurality of electrode plates can have a second thickness. The second thickness can be substantially the same as the first thickness. Alternatively, the second thickness can be greater or smaller than the first thickness. 
     Further areas of applicability will become apparent from the description provided herein. The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. 
    
    
     
       DRAWINGS 
       The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure. The drawings provide a further understanding of the disclosure and form a part of the present application, wherein: 
         FIG.  1    is a schematic diagram of a liquid level sensor in prior art; 
         FIG.  2    is a schematic diagram of an electrode plate according to an embodiment of the present disclosure; 
         FIG.  3    is a first schematic diagram of a support plate according to an embodiment of the present disclosure; 
         FIG.  4    is a schematic diagram of a liquid level sensor according to an embodiment of the present disclosure; 
         FIG.  5    is a second schematic diagram of an electrode plate according to an embodiment of the present disclosure; 
         FIG.  6    is a second schematic diagram of a support plate according to an embodiment of the present disclosure; 
         FIG.  7    is a second schematic diagram of a liquid level sensor according to an embodiment of the present disclosure; 
         FIG.  8    is a third schematic diagram of an electrode plate according to an embodiment of the present disclosure; 
         FIG.  9    is a third schematic diagram of a support plate according to an embodiment of the present disclosure; 
         FIG.  10    is a third schematic diagram of a liquid level sensor according to an embodiment of the present disclosure; 
         FIG.  11    is a fourth schematic diagram of an electrode plate according to an embodiment of the present disclosure; 
         FIG.  12    is a fourth schematic diagram of a support plate according to an embodiment of the present disclosure; and 
         FIG.  13    is a fourth schematic diagram of a liquid level sensor according to an embodiment of the present disclosure. 
     
    
    
     Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings. 
     DETAILED DESCRIPTION 
     Example embodiments will now be described more fully with reference to the accompanying drawings. The example embodiments are provided so that this disclosure will be thorough, and will fully convey the scope to those who are skilled in the art. Numerous specific details are set forth such as examples of specific components, devices, and methods, to provide a thorough understanding of embodiments of the present disclosure. It will be apparent to those skilled in the art that specific details need not be employed, that example embodiments may be embodied in many different forms and that neither should be construed to limit the scope of the disclosure. In some example embodiments, well-known processes, well-known device structures, and well-known technologies are not described in detail. 
     This disclosure provides various embodiments of a liquid level sensor  2 ,  5 ,  8  and  11 . With specific reference to  FIGS.  8 ,  9  and  10   , an exemplary liquid level sensor  8  can include a first portion or metal cover plate  1001  and a second portion or probe portion  803 . 
     The first portion or metal cover plate  1001  can take the form of a hermetic terminal assembly. The first portion can include a cap-shaped metal body member  804  having a generally flat top surface  805  including one or more apertures  806 . A peripheral side wall  807  can extend from the top surface and can include a flanged portion  808  at a distal perimeter of the side wall. One or more electrically conductive pins  1002  can pass through the apertures  806  in the top surface  805  of the body member  804  and extend from a first side of the metal cover plate  1001  to a second side of the metal cover plate  1001 . A sealing glass  809  can be disposed between the pins  1002  and the apertures  806  in the body member  804  to hermetically seal the pins  1002  to the body member  804  and electrically isolate to the pins  1002  from the body member  804  and from one another. 
     The second portion or probe portion  803  can include a plurality of generally planar electrode plates  801  located on the second side of the metal cover plate  1001 . The electrode plates  801  are supported by a plurality of support plates  901 , respectively, so that a fixed gap or distance d can be maintained between the electrode plates  801 . Each electrode plate  801  of the plurality of electrode plates  801  includes a planar portion  810  and a wing portion  802 . The wing portion  802  extends outwardly from the planar portion  810  of the electrode plate  801 . A respective conductive pin  1002  can be electrically connected or attached to the wing portion  802  of a corresponding electrode plate  801 . 
     The liquid level sensor  11  shown in  FIGS.  8 - 10    adopts multiple electrode plates  801  and a plurality of conductive pins  1002 . Each electrode plate  801  includes a wing portion  802  that is connected to a respective one of the plurality of conductive pin  1002 , such as by welding. The wing portion  802  extends outwardly from the electrode plate  801  and the wing portion  802  can be integrally formed with the electrode plate  801 . This configuration improves the stability of the connection between the electrode plate  801  and the conductive pin  802 , and improves the stability of the liquid level sensor  11 . 
     As a preferred embodiment, the wing portion  802  comprises a bent portion or bent part  8021  and a conductive portion or conductive part  8022 . In this preferred embodiment, the bent part  8021  can provide a certain amount of metal elasticity, and provide buffer elasticity for the electrode plate  801  and the connected conductive pin  1002 , and in various working environments of the liquid level sensor  11 . In this way, the stability of the connection between the electrode plate  801  and the conductive pin  1002  is improved. The conductive part  8022  of the wig portion  802  is electrically connected to the conductive pin  1002  to enable an electrical signal to be conducted or transmitted from the electrode plate  801  to the pin  1002 . 
     In various exemplary implementations, the wing portion can be arranged at multiple positions along the planar portion of the support plate, for example: 
     Configuration 1: The wing portion is located in the middle of multiple electrode plates (as shown in  FIGS.  2 ,  3 ,  4 ,  5 ,  6 ,  7 ,  11 ,  12 , and  13   ). 
     Configuration 2: The wing portion is located at the first end of each electrode plate in the plurality of electrode plates, and the distance between the first end of each electrode plate and the metal cover plate is smaller than the distance between the second end of each electrode plate and the metal cover plate. 
     Preferably, the conductive part is located at a position that offset a distance from the planar portion of the electrode plate. The conductive pin is connected to the conductive part. In a preferred embodiment, the conductive pin is electrically connected to an attachment portion of the conductive part for signal conduction or transmission between the electrode plate to the conductive pin. 
     In the exemplary implementations, a first surface or attachment portion of the conductive part is connected to the conductive pin; or, a second surface of the conductive part is connected to the conductive pin. As such, a variety of configurations can be employed to connect the wing portion to the conductive pin, and different positions of the conductive pin can be accommodated, which improves the diversity of possible connections. 
     In the exemplary implementations, in order to ensure the accuracy of the measurement of the liquid level sensor, the interval or distance between the electrode plates should be kept constant. Using multiple support plates (e.g., 2 support plates), one of the multiple support plates can be arranged at a first end of the electrode plates. The other support plate of the multiple support plates can be arranged at a second end of the electrode plates. Alternatively, one support plate of the multiple support plates can be arranged at a second end of the electrode plates, and the other support plate of the multiple support plates can be arranged between the wing portion and the second end of the electrode plates. Multiple support plates are used to ensure a constant interval or gap, and the support plates can be arranged in a variety of ways, which improves the diversity of the support plate settings, ensures a constant interval, and improves the accuracy of the liquid level sensor measurement. 
     Preferably, a plurality of electrode plates are arranged so the respective planar portions of the electrode planes are parallel to one another and the respective wing portions of the electrode planes extend outwardly from the planar portions in a direction away from one another. 
     In this embodiment, one or more convex parts (i.e., pads or protrusions are provided on the conductive part of the wing portion. This arrangement can make the welding of the conductive pin to the conductive part more precise, make the connection between the electrode plate and the conductive pin more stable, and make the measurement of the liquid level sensor more accurate. 
     The following describes with multiple examples. 
     EXAMPLE ONE 
     This embodiment provides a liquid level sensor as shown in  FIGS.  2 ,  3  and  4   . 
     The liquid level sensor includes a metal cover plate  401 , a plurality of conductive pins  402 , each conductive pin passing through the metal cover plate  401 , a plurality of electrode plates  201 , a plurality of support plates  301 , each support plate  301  supporting the plurality of electrode plates  201 , so that the plurality of electrode plates  201  maintain a fixed interval, gap or distance. Each electrode plate  201  of the electrode plate  201  includes a wing portion  202  extending outward from a planar portion of the electrode plate  201 , and the conductive pin  402  is connected to the wing portion  202 . 
     In this preferred embodiment, the wing portion  202  has a bent part  2021  and a conductive part  2022 . The bent part  2021  can provide a certain amount of metal elasticity, and provide buffer elasticity for the electrode plate  201  and the respective connected conductive pin  402 . In various working environments of the liquid level sensor, this can improve the stability of the connection between the electrode plate and the conductive pin, and the conductive part is connected to the conductive pin for signal conduction or transmission. 
     In this embodiment, the wing portion  202  is located in the middle of the plurality of electrode plates  201  (i.e., between a first end  2023  and a second end  2024  of the electrode plates  201 ). Such an implementation is convenient for production. 
     EXAMPLE TWO 
     This embodiment provides a liquid level sensor as shown in  FIGS.  5 ,  6  and  7   . 
     The liquid level sensor can include a metal cover plate  701 , at least one conductive pin  702  passing through the metal cover plate  701 , multiple electrode plates  501 , multiple support plates  501 , each supporting, the electrode plates  501  so that a fixed interval, gap or distance between the multiple electrode plates  501  is maintained. Each electrode plate  501  of the multiple electrode plate  501  includes a wing portion  502  extending outward from a planar portion of the electrode plate  501 . The wing portion  502  is connected to the conductive pin  702 . 
     The wing portion  502  includes a bent part  5021  and a conductive part  5022 . The bent part can provide a certain amount of metal elasticity, and provide buffer elasticity for the electrode plate and the connected conductive pin. In various working environments of the liquid level sensor this can improve the stability of the connection between the electrode plate and the conductive pin, and the conductive part is electrically connected to the conductive pin for signal transmission. 
     In this embodiment, the wing portion  502  is located in the middle of the plurality of electrode plates  501  (i.e., between a first end  5023  and a second end  5024  of the electrode plates  501 ). Such an implementation is convenient for production. 
     EXAMPLE THREE 
     This embodiment provides a liquid level sensor as shown in  FIGS.  8 ,  9  and  10   . 
     The liquid level sensor includes a metal cover plate  1001 , at least one conductive pin  1002  passing through the metal cover plate  1001 , a plurality of electrode plates  801 , a plurality of support plates  901  supporting the plurality of electrode plates  801  so that the plurality of electrode plates  801  maintain a fixed interval, gap or distance from one another. Each electrode plate  801  includes a wing portion  802  extending outward from a planar portion of the electrode plate  801 . A corresponding conductive pin  1002  is connected to each wing portion  802 . 
     In this preferred embodiment, the wing portion has a bent portion or part  8021  and a conductive portion or part  8022 . The bent part can provide a certain amount of metal elasticity, and provide buffer elasticity for the electrode plate and the connected conductive pin. In various working environments of the liquid level sensor, this can improve the stability of the connection between the electrode plate and the conductive pin. The conductive part is electrically connected to the conductive pin for signal conduction or transmission. 
     In this embodiment, the wing portion  802  is located at the first end  8023  of each electrode plate  801  of the plurality of electrode plates, and a distance between the first end  8023  and the metal cover plate  1001  is less than a distance between the second end  8024  of each electrode plate  801  and the metal cover plate  1001 . Such an embodiment makes the relative area of the electrode plate relatively intact (i.e., continuous) and can improve the accuracy of the liquid level sensor measurement. 
     EXAMPLE FOUR 
     This embodiment provides a liquid level sensor, as shown in  FIGS.  11 ,  12  and  13   . 
     The liquid level sensor includes a metal cover  1301 , a plurality of conductive pins  1302 , each conductive pin penetrating or passing through the metal cover  1301 , a plurality of electrode plates  1101 , a plurality of support plates  1201 , each supporting the plurality of electrode plates  1101  so that the multiple electrode plates  1101  are maintained at a fixed interval, gap or distance apart from one another. Each electrode plate  1101  of the plurality of electrode plates  1101  has a wing portion  1102 , the wing portion  1102  extending outward from a planar portion of the electrode plate  1101 , and the wing portion  1102  is connected to a conductive pin  1302 . 
     In this preferred embodiment, the wing portion  1102  includes a bent part or portion  11021  and a conductive part or portion  11022 . The bent part can provide a certain amount of metal elasticity, and provide buffer elasticity for the electrode plate and the connected conductive pin. In various working environments of the liquid level sensor, this can improve the stability of the connection between the electrode plate and the conductive pin. The conductive part is electrically connected to the conductive pin for signal conduction or transmission. 
     In this embodiment, the wing portion  1102  is located intermediate the opposite ends  11023  and  11024  of the plurality of electrode plates  1101 . Such an implementation is convenient for production. 
     To sum up, through the above technical solutions in the present invention, the liquid level sensor includes: a metal cover plate; a conductive pin through which the conductive pin penetrates the metal cover plate; a plurality of electrode plates; and a plurality of support plates supporting the plurality of electrode plates respectively, so that a fixed interval is maintained between the plurality of electrode plates; each electrode plate of the plurality of electrode plates has a wing portion, the wing portion is connected to the conductive pin, and the wing portion extends outward from each electrode plate . The wing portion and the electrode plate are integrally formed, and the wing portion is connected to the conductive pin, which improves the stability of the connection between the electrode plate and the conductive pin and improves the working stability of the liquid level sensor. 
     The above mentioned is merely the preferred embodiments of the present invention but not to limit the present invention. Various alterations and changes to the present invention are apparent to the person skilled in the art. Any modifications, equivalent substitutions, improvements etc. within the spirit and principle of the present invention should be covered by the protection scope of the present invention. 
     The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.