Patent Description:
Industrial and commercial applications may use electrolyte-based electrochemical gas sensors to detect the presence of various gasses. However, conventional electrolyte-based electrochemical gas sensor designs are prone to decreased measurement sensitivity and even failure due to evaporation of the electrolyte contained therein.

<CIT> discloses a gas sensor that includes known types of electrodes such as sensing electrodes, counter electrodes or reference electrodes to sense the presence of a predetermined gas. In addition, at least one diagnostic electrode is carried in the sensor. The diagnostic electrode implements at least one diagnostic function without substantially impairing the gas sensing function. The diagnostic electrode is immersed in sensor electrolyte.

<CIT> discloses a method comprising scanning a diagnostic micro - electrode of an electrochemical sensor using scanning voltammetry at a plurality of electrolyte concentrations; generating a variable set of readings from the first scanning voltammetry scan using a potential difference between a strong hydrogen adsorption peak and an oxide reduction peak and/or oxide formation peak at each of the plurality of electrolyte concentrations; and determining a correlation by plotting the variable set of readings and the plurality of electrolyte concentrations.

<CIT> discloses an electrochemical gas sensor for sensing two different toxic gases and having a housing with at least one gas inlet to allow gas to diffuse onto a electrode assembly comprising two sensing electrodes formed on a common support with a gap between the two electrodes, the gas passing through a filter housing divided into separate compartments for gas diffusion through each compartment to a respective selected electrode, one compartment allowing the passage of unfiltered gas and the other compartment containing a gas filter to permit passage of a selected gas onto the respective electrode, the filter housing also sealing against the support in the gap between the two electrodes.

<CIT> discloses an electrochemical gas sensor assembly comprising an electrochemical gas sensor including sensing and counter electrodes , an intervening body of electrolyte contacting the electrodes, a diffusion control for controlling the diffusion of gas to the sensing electrode wherein a gas to be sensed is reacted at the sensing electrode, the electrode being connected in an electrical circuit, the circuit including a monitor for monitoring current flow in the circuit related to the concentration of the gas being sensed. The assembly further comprises an electrical biasing system operable in a test mode to bias the sensing electrode relative to the counter electrode to a potential at which oxygen is reduced at the sensing electrode and evolved at the counter electrode, the monitor providing an output indicating the operating condition of the sensor.

<CIT> discloses that an impedance in an electrochemical gas sensor can be measured by connecting at least one pin in an integrated circuit to at least one electrode in an electrochemical gas sensor, using a damping capacitor to connect the at least one pin in the integrated circuit to an electrical ground, applying a voltage to the electrochemical gas sensor to provide a bias voltage to at least one electrode in the electrochemical gas sensor, receiving a current from at least one electrode in the electrochemical gas sensor, determining a measured gas amount from the received current, activating a switch located within the integrated circuit to isolate the damping capacitor from the at least one pin in the integrated circuit, and measuring an impedance of the electrochemical gas sensor using an excitation signal while the at least one damping capacitor is isolated from the at least one electrode in the electrochemical gas sensor.

Applicant has identified a number of deficiencies and problems associated with conventional electrolyte-based gas sensors. Through applied effort, ingenuity, and innovation, many of these identified problems have been solved by developing solutions that are included in embodiments of the present disclosure, many examples of which are described in detail herein.

Having described certain example embodiments of the present disclosure in general terms above, reference will now be made to the accompanying drawings, which illustrate example embodiments and features of the present disclosure and are not necessarily drawn to scale. It will be understood that the components and structures illustrated in the drawings may or may not be present in various embodiments of the disclosure described herein. Accordingly, some embodiments or features of the present disclosure may include fewer or more components or structures than those shown in the drawings while not departing from the scope of the disclosure.

The following description should be read with reference to the drawings wherein like reference numerals indicate like elements throughout the several views. The detailed description and drawings show several embodiments which are meant to be illustrative of the disclosure. It should be understood that any numbering of disclosed features (e.g., first, second, etc.) and/or directional terms used in conjunction with disclosed features (e.g., front, back, top, bottom, side, and the like) are relative terms indicating illustrative relationships between the pertinent features.

It should be understood at the outset that although illustrative implementations of one or more aspects are illustrated below, the disclosed assemblies, systems, and methods may be implemented using any number of techniques, whether currently known or not yet in existence. The disclosure should in no way be limited to the illustrative implementations, drawings, and techniques illustrated below, but may be modified within the scope of the appended claims. While values for dimensions of various elements are disclosed, the drawings may not be to scale.

The word "example," when used herein, is intended to mean "serving as an example, instance, or illustration. " Any implementation described herein as an "example" is not necessarily preferred or advantageous over other implementations.

Traditional gas sensors containing liquid electrolytes can be prone to changes in the electrolyte due to evaporation during life. For aqueous electrolytes it is generally the water content of the electrolyte that changes, and some methods have been proposed to enable the resulting electrolyte concentration to be measured. However, some electrolytes themselves are volatile and may tend to evaporate over time, as a function of temperature. Examples of such electrolytes include propylene carbonate and acetonitrile. Often these electrolytes may be single component electrolytes. As a result, there may be no change in concentration and therefore no property of the electrolyte itself that can be measured.

Failure of such types of traditional gas sensors may occur when there is no longer enough electrolyte to maintain sufficient ionic contact between the electrodes or when there are sufficient dry paths through the electrolyte for gases to reach the reference electrode, causing drift in performance and potential loss of sensitivity. While a simple conductivity measurement at the sensing electrode might be sufficient to detect failure in some instances, that simple conductivity measurement might not be sufficiently sensitive to detect failure and may not give any advance warning of impending failure or prediction of remaining life.

The disclosure solves these problems by describing a unique design for an electrochemical gas sensor that makes use of a differential wicking approach to sensor design. The electrochemical gas sensor disclosed herein comprises two types of fibrous material: one or more separators (e.g., made of separator material such as grade GF/A glass fiber having a mean particle filtration size of about <NUM>), which may be used separate the electrodes; and a wick (e.g., made of a wick material such as BS2000 glass fiber having a mean particle filtration size of about <NUM>), used to fill or partially fill a reservoir and to feed electrolyte to the separators. The wick material is designed to be less hydrophilic than the one or more separators so that when the wick material is in contact with the separator material and the electrolyte volume decreases (e.g., due to evaporation), the wick material dries out before the separator material.

The electrochemical gas sensor disclosed herein is configured to perform a conductivity measurement (e.g., Reflex or Capa type pulse test; single or multiple frequency impedance spectroscopy) across the wick material rather than the typical conductivity measurement across the one or more separators. This conductivity measurement will allow the electrochemical gas sensor to monitor the drying of the wick material and provide advance warning of impending failure, since the wick material will dry out before the one or more separators. In some instances, the conductivity measurement is more than a simple "wet vs. dry" measurement since there may be some variation in conductivity as the wick becomes relatively dry and percolation effects result in an increasing impedance.

The electrochemical gas sensor disclosed herein comprises one or more auxiliary electrodes to measure the conductivity through the wick material. Although the disclosure describes the features of the auxiliary electrode with reference to an electrochemical gas sensor, the auxiliary electrode disclosed herein may be applied in any suitable detector, sensor, gauge, instrument, or application where measurement of electrolyte content is desired.

Methods of measuring and compensating for electrolyte changes, such as those disclosed herein, are critical to the development of environmental compensation algorithms, fault diagnostics, and advance failure warnings for electrolyte-based electrochemical gas sensors.

<FIG>, <FIG>, <FIG>, and <FIG> illustrate exploded views of example electrochemical gas sensors configured to measure electrolyte content. For example, <FIG> illustrates an exploded view <NUM> of an example electrochemical gas sensor 100A, <FIG> illustrates an exploded view <NUM> of an example electrochemical gas sensor 100B, <FIG> illustrates an exploded view <NUM> of an example electrochemical gas sensor 100C, and <FIG> illustrates an exploded view <NUM> of an example electrochemical gas sensor 100D, As used herein, electrochemical gas sensor <NUM> may comprise any combination of components, structures, and features discussed with reference to example electrochemical gas sensor 100A, example electrochemical gas sensor 100B, example electrochemical gas sensor 100C, or example electrochemical gas sensor 100D, including the addition or omission of components, structures, and features.

The electrochemical gas sensor <NUM> (e.g., example electrochemical gas sensor 100A, example electrochemical gas sensor 100B, example electrochemical gas sensor 100C, example electrochemical gas sensor 100D, or a combination thereof, including, but not limited to, any combination of components, structures, and features discussed with reference thereto) may be a hardware device with embedded software configured to measure, detect, and transmit data (e.g., temperature, pressure, motion, and other suitable data). The embedded software may be configured to run in an apparatus, device, or unit (e.g., firmware). The electrochemical gas sensor <NUM> may be a carbon monoxide sensor. The electrochemical gas sensor <NUM> may be applicable to other sensor and gas types.

As shown in <FIG>, <FIG>, <FIG>, and <FIG>, the electrochemical gas sensor <NUM> may comprise a top cap part <NUM> having an aperture defining a capillary hole in the center of the top cap part <NUM> to allow gas access to the sensing electrode <NUM>.

The electrochemical gas sensor <NUM> may comprise a filter material <NUM>. The filter material <NUM> may be optionally provided depending on sensor type of the example electrochemical gas sensor <NUM>. For example, <FIG>, <FIG>, and <FIG> show an example electrochemical gas sensor 100A, an example electrochemical gas sensor 100C, and an example electrochemical gas sensor 100D that includes the filter material <NUM>. In another example, <FIG> shows an example electrochemical gas sensor 100B that does not include the filter material <NUM>.

The electrochemical gas sensor <NUM> may comprise a porous polytetrafluoroethylene (PTFE) film tape <NUM> to support the sensing electrode <NUM>. The porous PTFE film tape <NUM> may be sealed against the top cap part <NUM> to retain electrolyte within the electrochemical gas sensor <NUM> while allowing gas to diffuse from the capillary hole in the center of the top cap part <NUM> to the sensing electrode <NUM> or, in some instances, through the filter material <NUM> to the sensing electrode <NUM>.

The electrochemical gas sensor <NUM> comprises a sensing electrode <NUM> which may be deposited on porous PTFE film tape <NUM>. The sensing electrode <NUM> may be deposited on the bottom surface of the porous PTFE film tape <NUM> (e.g., facing downwards) and thus is not visible in in <FIG>, <FIG>, <FIG>, and <FIG>. The electrochemical gas sensor <NUM> may comprise a connecting wire <NUM> to electrically connect the sensing electrode <NUM> to a first pin of the pins <NUM>.

The electrochemical gas sensor <NUM> comprises a separator material <NUM>. The separator material is made of a hydrophilic material, such as a glass fiber material (e.g., grade GF/A glass fiber having a mean particle filtration size of about <NUM>).

The electrochemical gas sensor <NUM> comprises a reference electrode <NUM> deposited onto the top surface of a porous PTFE film tape <NUM> (e.g., facing upwards). The electrochemical gas sensor <NUM> may comprise a connecting wire <NUM> to electrically connect the reference electrode <NUM> to a second pin of the pins <NUM>.

The electrochemical gas sensor <NUM> comprises a porous PTFE film tape <NUM> to support and electrically separate the reference electrode <NUM> and the counter electrode <NUM>.

The electrochemical gas sensor <NUM> comprises a counter electrode <NUM> deposited onto a bottom surface of the porous PTFE film tape <NUM> (e.g., facing downwards). The electrochemical gas sensor <NUM> may comprise a connecting wire <NUM> to electrically connect the counter electrode <NUM> to a third pin of the pins <NUM>.

The electrochemical gas sensor <NUM> may comprise a separator material <NUM>. The separator material <NUM> may be made of a hydrophilic material, such as a glass fiber material (e.g., grade GF/A glass fiber having a mean particle filtration size of about <NUM>). The separator material <NUM> may be optionally provided to maintain wetting of the counter electrode <NUM> as the wick material <NUM> dries out (e.g., as the volume of the electrolyte content in the wick material <NUM> decreases). For example, <FIG>, <FIG>, and <FIG> show an example electrochemical gas sensor 100A, an example electrochemical gas sensor 100C, and an example electrochemical gas sensor 100D that includes the separator material <NUM>. In another example, <FIG> shows an example electrochemical gas sensor 100B that does not include the separator material <NUM>.

The electrochemical gas sensor <NUM> comprises a wick material <NUM>. The wick material <NUM> is made of a hydrophilic material (e.g., BS2000 glass fiber having a mean particle filtration size of about <NUM>). The wick material <NUM> is less hydrophilic than the separator material <NUM>, the separator material <NUM>, or both in order to absorb excess electrolyte material but selectively give up electrolyte material to the separator material <NUM>, the separator material <NUM>, or both as the electrolyte material in the wick material <NUM> dries out.

The electrochemical gas sensor <NUM> may comprise an epoxy material <NUM>. The epoxy material <NUM> may be made of an epoxy material, such as a two-part epoxy amino resin. The epoxy material <NUM> may be optionally provided to protect the inner surface of the pins <NUM> (e.g., the portion of the pins <NUM> disposed within the cavity structure of the housing part <NUM>) from contact with electrolyte material. For example, <FIG>, <FIG>, and <FIG> show an example electrochemical gas sensor 100A, an example electrochemical gas sensor 100C, and an example electrochemical gas sensor 100D that includes the epoxy material <NUM>. In another example, <FIG> shows an example electrochemical gas sensor 100B that does not include the epoxy material <NUM>.

The electrochemical gas sensor <NUM> comprises a housing part <NUM> which may be sealed against the top cap part <NUM>. The filter material <NUM>, the porous PTFE film tape <NUM>, the sensing electrode <NUM>, the connecting wire <NUM>, the separator material <NUM>, the reference electrode <NUM>, the connecting wire <NUM>, the porous PTFE film tape <NUM>, the counter electrode <NUM>, the connecting wire <NUM>, the separator material <NUM>, the wick material <NUM>, the epoxy material <NUM>, the inner surface of the pins <NUM>, the auxiliary electrode <NUM>, the connecting wire <NUM>, the film tape <NUM>, the auxiliary electrode <NUM>, the connecting wire <NUM>, the porous PTFE film tape <NUM>, the additional separator disposed between the connecting wire <NUM> and the wick material <NUM>, or a combination thereof are configured to be disposed in the cavity structure of the housing part <NUM> and, in some instances, sealed in the cavity structure of the housing part <NUM> by the top cap part <NUM>.

The electrochemical gas sensor <NUM> may comprise a plurality of pins <NUM> protruding through housing part <NUM> to provide electrical connection from sensing electrode <NUM>, reference electrode <NUM>, counter electrode <NUM>, auxiliary electrode <NUM> (or connecting wire <NUM>), auxiliary electrode <NUM> (or connecting wire <NUM>), or a combination thereof to external circuitry, such as the electrolyte content monitoring circuitry <NUM> shown in <FIG>.

The electrochemical gas sensor <NUM> comprises an electrolyte material, such as a liquid electrolyte. The electrolyte material is disposed in the wick material <NUM>, the separator material <NUM>, the separator material <NUM>, the additional separator disposed between the connecting wire <NUM> and the wick material <NUM>, the cavity structure of the housing part <NUM>, or a combination. According to the present invention the electrolyte material is a liquid electrolyte disposed at least in the wick material <NUM> and the separator material <NUM>.

The electrochemical gas sensor <NUM> comprises an auxiliary electrode <NUM> to provide for an impedance measurement across the wick material <NUM>. The electrochemical gas sensor <NUM> may comprise a connecting wire <NUM> to electrically connect the auxiliary electrode <NUM> to a fourth pin of the pins <NUM>. The electrochemical gas sensor <NUM> may comprise a film tape <NUM>. The auxiliary electrode <NUM> may be deposited on a top surface of the film tape <NUM> (e.g., facing upwards). The film tape <NUM> may be a porous PTFE film tape. The film tape <NUM> may be a non-porous tape. The film tape <NUM> may be optionally provided to support the auxiliary electrode <NUM>. For example, <FIG>, <FIG>, and <FIG> show an example electrochemical gas sensor 100A, an example electrochemical gas sensor 100B, and an example electrochemical gas sensor 100D that includes the auxiliary electrode <NUM> deposited on the top surface of the film tape <NUM>. In another example, <FIG> shows an example electrochemical gas sensor 100C that does not include the auxiliary electrode <NUM> or the film tape <NUM>. Rather, in <FIG>, the example electrochemical gas sensor 100C uses the connecting wire <NUM> itself as the auxiliary electrode.

The electrochemical gas sensor <NUM> may comprise an additional separator disposed between the connecting wire <NUM> and the wick material <NUM>.

As shown in <FIG>, the example electrochemical gas sensor <NUM> may comprise an additional auxiliary electrode <NUM> to provide for an impedance measurement across the wick material <NUM>. The electrochemical gas sensor <NUM> may comprise a connecting wire <NUM> to electrically connect the additional auxiliary electrode <NUM> to a fifth pin of the pins <NUM>. The electrochemical gas sensor <NUM> may comprise a porous PTFE film tape <NUM>. The additional auxiliary electrode <NUM> may be deposited on a bottom surface of the porous PTFE film tape <NUM> (e.g., facing downwards). The porous PTFE film tape <NUM> may be optionally provided to support the additional auxiliary electrode <NUM>. For example, <FIG> shows an example electrochemical gas sensor 100D that includes the additional auxiliary electrode <NUM> deposited on the bottom surface of the porous PTFE film tape <NUM>. In another example, the electrochemical gas sensor <NUM> may not include the additional auxiliary electrode <NUM> or the porous PTFE film tape <NUM>. Rather, such an example electrochemical gas sensor <NUM> may use the connecting wire <NUM> itself as an auxiliary electrode.

The electrochemical gas sensor (e.g., electrochemical gas sensor <NUM>) comprises a separator material (e.g., separator material <NUM>) comprising a first separator material surface (e.g., the top surface of the separator material <NUM>) and a second separator material surface (e.g., the bottom surface of the separator material <NUM>) opposite the first separator material surface.

The electrochemical gas sensor comprises a first electrode (e.g., sensing electrode <NUM>) disposed on the first separator material surface of the separator material (e.g., the top surface of the separator material <NUM>). The first electrode may be a sensing electrode (e.g., sensing electrode <NUM>). The electrochemical gas sensor (e.g., electrochemical gas sensor <NUM>) may comprise a first connecting wire (e.g., connecting wire <NUM>) configured to connect the first electrode to a first electrical contact (e.g., a first pin of pins <NUM>).

The electrochemical gas sensor comprises a second electrode (e.g., reference electrode <NUM>) disposed on the second separator material surface of the separator material (e.g., the top surface of the separator material <NUM>). The second electrode may be a reference electrode (e.g., reference electrode <NUM>). The electrochemical gas sensor (e.g., electrochemical gas sensor <NUM>) may comprise a second connecting wire (e.g., connecting wire <NUM>) configured to connect the second electrode to a second electrical contact (e.g., a second pin of pins <NUM>).

The electrochemical gas sensor comprises a wick material (e.g., wick material <NUM>) comprising a first wick material surface (e.g., the top surface of the wick material <NUM>) and a second wick material surface (e.g., the bottom surface of the wick material <NUM>) opposite the first wick material surface. The wick material is designed to be less hydrophilic than the one or more separators so that when the wick material and the one or more separators are in contact and the electrolyte volume decreases (e.g., due to evaporation), the wick material dries out before the one or more separators. The separator material (e.g., separator material <NUM>) comprises a first hydrophilic material (e.g., a material such as grade GF/A glass fiber having a mean particle filtration size of about <NUM>), the wick material comprises a second hydrophilic material (e.g., made of material such as BS2000 glass fiber having a mean particle filtration size of about <NUM>), and the first hydrophilic material is more hydrophilic than the second hydrophilic material.

The electrochemical gas sensor comprises a third electrode (e.g., counter electrode <NUM>) disposed facing the first wick material surface of the wick material (e.g., the top surface of the wick material <NUM>). The third electrode may be a counter electrode (e.g., counter electrode <NUM>). The electrochemical gas sensor (e.g., electrochemical gas sensor <NUM>) may comprise a third connecting wire (e.g., connecting wire <NUM>) configured to connect the third electrode to a third electrical contact (e.g., a third pin of pins <NUM>).

As shown in <FIG>, the third electrode (e.g., counter electrode <NUM>) is disposed on the first wick material surface of the wick material (e.g., the top surface of the wick material <NUM>).

As shown in <FIG> and <FIG>, the separator material (e.g., the separator material <NUM>) may be a first separator material, and the electrochemical gas sensor <NUM> may comprise a second separator material (e.g., the separator material <NUM>) comprising a third separator material surface (e.g., the top surface of the separator material <NUM>) and a fourth separator material surface (e.g., the bottom surface of the separator material <NUM>) opposite the third separator material surface. The third electrode (e.g., counter electrode <NUM>) may be configured to be disposed on the third separator material surface of the second separator material (e.g., the top surface of the separator material <NUM>). The third separator material surface of the second separator material (e.g., the top surface of the separator material <NUM>) may be configured to be disposed on the third electrode(e.g., counter electrode <NUM>), and the fourth separator material surface of the second separator material (e.g., the bottom surface of the separator material <NUM>) may be configured to be disposed on the first wick material surface of the wick material (e.g., the top surface of the wick material <NUM>).

The electrochemical gas sensor comprises a fourth electrode (e.g., auxiliary electrode <NUM>, connecting wire <NUM>) disposed on the second wick material surface of the wick material (e.g., the bottom surface of the wick material <NUM>). The fourth electrode is configured to measure an electrical conductivity through the wick material. The fourth electrode may be an auxiliary electrode (e.g., auxiliary electrode <NUM>). The fourth electrode may be a wire electrode (e.g., connecting wire <NUM>). The fourth electrode may be an area electrode (e.g., auxiliary electrode <NUM>). The fourth electrode may comprise platinum. The fourth electrode may comprise carbon. The fourth electrode may be porous. The fourth electrode may be non-porous. The fourth electrode may be disposed on a surface of a PTFE film tape (e.g., the top surface of the film tape <NUM> wherein the film tape <NUM> is a PTFE film tape). The electrochemical gas sensor (e.g., electrochemical gas sensor <NUM>) may comprise a fourth connecting wire (e.g., connecting wire <NUM>) configured to connect the fourth electrode to a fourth electrical contact (e.g., a fourth pin of pins <NUM>).

The electrochemical gas sensor comprises a housing part (e.g., housing part <NUM>) comprising a cavity structure. The separator material (e.g., separator material <NUM>), the first electrode (e.g., sensing electrode <NUM>), the second electrode (e.g., reference electrode <NUM>), the wick material (e.g., wick material <NUM>), the third electrode (e.g., counter electrode <NUM>), and the fourth electrode (e.g., auxiliary electrode <NUM>, connecting wire <NUM>) are disposed in the cavity structure of the housing part (e.g., housing part <NUM>).

The electrochemical gas sensor may comprise, or be electrically connected to (e.g., via pins <NUM>), electrolyte content monitoring circuitry (e.g., electrolyte content monitoring circuitry <NUM> shown in <FIG>) in communication with the third electrode (e.g., counter electrode <NUM>) and the fourth electrode (e.g., auxiliary electrode <NUM>, connecting wire <NUM>), wherein the electrolyte content monitoring circuitry is configured to: measure an impedance between the fourth electrode (e.g., auxiliary electrode <NUM>, connecting wire <NUM>) and the third electrode (e.g., counter electrode <NUM>); and measure an electrical conductivity through the wick material (e.g., wick material <NUM>) based on the measured impedance.

The electrochemical gas sensor may comprise a top cap part (e.g., top cap part <NUM>) configured to be disposed on a surface of the housing part (e.g., housing part <NUM>). The top cap part may define an aperture configured to provide a capillary hole structure to allow gas access to the first electrode (e.g., sensing electrode <NUM>).

As shown in <FIG>, the electrochemical gas sensor may comprise a fifth electrode (e.g., auxiliary electrode <NUM>, connecting wire <NUM>) disposed on the first wick material surface (e.g., the top surface of the wick material <NUM>). The fifth electrode may be configured to measure an electrical conductivity through the wick material. The fifth electrode may be an auxiliary electrode (e.g., auxiliary electrode <NUM>). The fourth electrode may be a first auxiliary electrode, and the fifth electrode may be a second auxiliary electrode. The fifth electrode may be a wire electrode (e.g., connecting wire <NUM>). The fifth electrode may be an area electrode (e.g., auxiliary electrode <NUM>). The fifth electrode may comprise platinum. The fifth electrode may comprise carbon. The fifth electrode may be porous. The fifth electrode may be non-porous. The fifth electrode may be disposed on a surface of a PTFE film tape (e.g., the bottom surface of the porous PTFE film tape <NUM>). The electrochemical gas sensor (e.g., electrochemical gas sensor <NUM>) may comprise a fifth connecting wire (e.g., connecting wire <NUM>) configured to connect the fifth electrode to a fifth electrical contact (e.g., a fifth pin of pins <NUM>).

The electrochemical gas sensor may comprise, or be electrically connected to (e.g., via pins <NUM>), electrolyte content monitoring circuitry (e.g., electrolyte content monitoring circuitry <NUM> shown in <FIG>) in communication with the fourth electrode (e.g., auxiliary electrode <NUM>, connecting wire <NUM>) and the fifth electrode (e.g., auxiliary electrode <NUM>, connecting wire <NUM>). The electrolyte content monitoring circuitry may be configured to: measure an impedance between the fourth electrode (e.g., auxiliary electrode <NUM>, connecting wire <NUM>) and the fifth electrode (e.g., auxiliary electrode <NUM>, connecting wire <NUM>); and measure an electrical conductivity through the wick material based on the measured impedance.

The electrochemical gas sensor (e.g., electrochemical gas sensor <NUM>) comprises a wick material (e.g., wick material <NUM>) comprising a first wick material surface (e.g., the top surface of the wick material <NUM>) and a second wick material surface (e.g., the bottom surface of the wick material <NUM>) opposite the first wick material surface. The electrochemical gas sensor comprises a first electrode (e.g., counter electrode <NUM>, auxiliary electrode <NUM>, or connecting wire <NUM>) disposed on the first wick material surface (e.g., the top surface of the wick material <NUM>). The electrochemical gas sensor comprises a second electrode (e.g., auxiliary electrode <NUM> or connecting wire <NUM>) disposed on the second wick material surface (e.g., the bottom surface of the wick material <NUM>). The electrochemical gas sensor may comprise, or be electrically connected to (e.g., via pins <NUM>), electrolyte content monitoring circuitry (e.g., electrolyte content monitoring circuitry <NUM>) in communication with the first electrode (e.g., counter electrode <NUM>, auxiliary electrode <NUM>, or connecting wire <NUM>) and the second electrode (e.g., auxiliary electrode <NUM> or connecting wire <NUM>). The electrolyte content monitoring circuitry may be configured to measure an impedance between the second electrode and the first electrode. The electrolyte content monitoring circuitry may be further configured to measure an electrical conductivity through the wick material based on the measured impedance.

By measuring the impedance across the wick material, which preferentially dries out as the electrolyte evaporates, the electrochemical gas sensor may provide advance warning before the electrolyte volume becomes low enough for sensor performance to be degraded. For example, performance may be degraded when there is no longer sufficient electrolyte to maintain separator material <NUM> and optional separator material <NUM> in a fully wetted state.

The example electrochemical gas sensor <NUM> described with reference to <FIG> may be embodied by one or more computing apparatuses, such as apparatus <NUM> shown in <FIG>. As illustrated in <FIG>, the apparatus <NUM> may include processing circuitry <NUM>, memory <NUM>, input-output circuitry <NUM>, communications circuitry <NUM>, electrochemical gas monitoring circuitry <NUM>, electrochemical gas detection circuitry <NUM>, electrolyte content monitoring circuitry <NUM>, low electrolyte content detection circuitry <NUM>, and user interface circuitry <NUM>. The apparatus <NUM> may be configured to execute the operations described above with respect to <FIG> and below with respect to <FIG>. Although some of these components <NUM>-<NUM> are described with respect to their functional capabilities, it should be understood that the particular implementations necessarily include the use of particular hardware to implement such functional capabilities. It should also be understood that certain of these components <NUM>-<NUM> may include similar or common hardware. For example, two sets of circuitry may both leverage use of the same processor, network interface, storage medium, or the like to perform their associated functions, such that duplicate hardware is not required for each set of circuitry.

The use of the term "circuitry" as used herein with respect to components of the apparatus <NUM> therefore includes particular hardware configured to perform the functions associated with respective circuitry described herein. Of course, while the term "circuitry" should be understood broadly to include hardware, circuitry may also include software for configuring the hardware. For example, "circuitry" may include processing circuitry, storage media, network interfaces, input-output devices, and other components. Other elements of the apparatus <NUM> may provide or supplement the functionality of particular circuitry. For example, the processing circuitry <NUM> may provide processing functionality, memory <NUM> may provide storage functionality, and communications circuitry <NUM> may provide network interface functionality, among other features.

The processing circuitry <NUM> (and/or co-processor or any other processing circuitry assisting or otherwise associated with the processor) may be in communication with the memory <NUM> via a bus for passing information among components of the apparatus. The memory <NUM> may be non-transitory and may include, for example, one or more volatile and/or non-volatile memories. For example, the memory <NUM> may be an electronic storage device (e.g., a computer readable storage medium). In another example, the memory <NUM> may be a non-transitory computer-readable storage medium storing computer-executable program code instructions that, when executed by a computing system, cause the computing system to perform the various operations described herein. The memory <NUM> may be configured to store information, data, content, signals applications, instructions (e.g., computer-executable program code instructions), or the like, for enabling the apparatus <NUM> to carry out various functions in accordance with the present disclosure. For example, the memory <NUM> may be configured to store electrolyte content monitoring techniques; capacitance measurement techniques; impedance measurement techniques; monitored data; ranges of monitored data; ranges of frequencies (e.g., band-gap filters); electrolyte content monitoring signals; any other suitable data or data structures; or any combination or combinations thereof. It will be understood that the memory <NUM> may be configured to store partially or wholly any electronic information, data, data structures, embodiments, examples, figures, processes, operations, techniques, algorithms, instructions, systems, apparatuses, methods, or computer program products described herein, or any combination thereof.

The processing circuitry <NUM> may be embodied in a number of different ways and may, for example, include one or more processing devices configured to perform independently. Additionally or alternatively, the processing circuitry <NUM> may include one or more processors configured in tandem via a bus to enable independent execution of instructions, pipelining, multithreading, or a combination thereof. The use of the term "processing circuitry" may be understood to include a single core processor, a multi-core processor, multiple processors internal to the apparatus, remote or "cloud" processors, or a combination thereof.

The processing circuitry <NUM> may be configured to execute instructions stored in the memory <NUM> or otherwise accessible to the processing circuitry <NUM>. Alternatively or additionally, the processing circuitry <NUM> may be configured to execute hard-coded functionality. As such, whether configured by hardware or software methods, or by a combination of hardware with software, the processing circuitry <NUM> may represent an entity (e.g., physically embodied in circuitry) capable of performing operations according to the present disclosure while configured accordingly. As another example, when the processing circuitry <NUM> is embodied as an executor of program code instructions, the instructions may specifically configure the processor to perform the operations described herein when the instructions are executed.

The apparatus <NUM> may include input-output circuitry <NUM> that may, in turn, be in communication with processing circuitry <NUM> to provide output to the user and to receive input such as a command provided by the user. The input-output circuitry <NUM> may comprise a user interface, such as a graphical user interface (GUI), and may include a display that may include a web user interface, a GUI application, a mobile application, a client device, or any other suitable hardware or software. The input-output circuitry <NUM> may also include a keyboard, a mouse, a joystick, a display device, a display screen, a touch screen, touch areas, soft keys, a microphone, a speaker (e.g., a buzzer), a light emitting device (e.g., a red light emitting diode (LED), a green LED, a blue LED, a white LED, an infrared (IR) LED, an ultraviolet (UV) LED, or a combination thereof), or other input-output mechanisms. The processing circuitry <NUM>, input-output circuitry <NUM> (which may utilize the processing circuitry <NUM>), or both may be configured to control one or more functions of one or more user interface elements through computer-executable program code instructions (e.g., software, firmware) stored in a non-transitory computer-readable storage medium (e.g., memory <NUM>). Input-output circuitry <NUM> is optional and the apparatus <NUM> may not include input-output circuitry. For example, where the apparatus <NUM> does not interact directly with the user, the apparatus <NUM> may generate user interface data for display by one or more other devices with which one or more users directly interact and transmit the generated user interface data to one or more of those devices. For example, the apparatus <NUM>, using user interface circuitry <NUM>, may generate user interface data for display by one or more display devices and transmit the generated user interface data to those display devices.

The communications circuitry <NUM> may be any device or circuitry embodied in either hardware or a combination of hardware and software that is configured to receive or transmit data from or to a network or any other device, circuitry, or module in communication with the apparatus <NUM>. In this regard, the communications circuitry <NUM> may include, for example, a network interface for enabling communications with a wired or wireless communication network. For example, the communications circuitry <NUM> may include one or more network interface cards, antennae, buses, switches, routers, modems, and supporting hardware and/or software, or any other device suitable for enabling communications via a network. The communication interface may include the circuitry for interacting with the antenna(s) to cause transmission of signals via the antenna(s) or to handle receipt of signals received via the antenna(s). These signals may be transmitted or received by the apparatus <NUM> using any of a number of Internet, Ethernet, cellular, satellite, or wireless technologies, such as IEEE <NUM>, Code Division Multiple Access (CDMA), Global System for Mobiles (GSM), Universal Mobile Telecommunications System (UMTS), Long-Term Evolution (LTE), Bluetooth® v1. <NUM> through v5. <NUM>, Bluetooth Low Energy (BLE), infrared wireless (e.g., IrDA), ultra-wideband (UWB), induction wireless transmission, Wi-Fi, near field communications (NFC), Worldwide Interoperability for Microwave Access (WiMAX), radio frequency (RF), RFID, or any other suitable technologies.

The electrochemical gas monitoring circuitry <NUM> includes hardware components designed or configured to receive, process, generate, and transmit data, such as the presence of a particular gas (e.g., carbon monoxide). The electrochemical gas monitoring circuitry <NUM> may be in communication with an electrode (e.g., sensing electrode <NUM>) for monitoring the presence of a particular gas. The electrochemical gas monitoring circuitry <NUM> may be configured to generate an electrochemical gas monitoring signal and transmit the generated electrochemical gas monitoring signal to the electrochemical gas detection circuitry <NUM>.

The electrochemical gas detection circuitry <NUM> includes hardware components designed or configured to receive, process, generate, and transmit data, such as electrochemical gas monitoring signals. The electrochemical gas detection circuitry <NUM> may analyze the electrochemical gas monitoring signal to determine that the presence of a particular gas has been detected. For example, the electrochemical gas detection circuitry <NUM> may generate a root mean square (RMS) electrochemical gas monitoring signal based on the electrochemical gas monitoring signal. The electrochemical gas detection circuitry <NUM> may detect the presence of a particular gas when the RMS electrochemical gas monitoring signal exceeds a predetermined electrochemical gas monitoring threshold value. In response to detecting the presence of the particular gas, the electrochemical gas detection circuitry <NUM> may generate an electrochemical gas alert signal and transmit the electrochemical gas alert signal to the input-output circuitry <NUM>, the communications circuitry <NUM>, or both for alerting a user or a system (e.g., an alarm system, a safety shut down system) that the presence of a particular gas has been detected.

The electrolyte content monitoring circuitry <NUM> includes hardware components designed or configured to receive, process, generate, and transmit data, such as electrolyte content monitoring signals. The electrolyte content monitoring circuitry <NUM> may be configured to measure an impedance between a pair of electrodes disposed facing or on the wick material (e.g., wick material <NUM>). The electrolyte content monitoring circuitry <NUM> may be configured to measure an electrical conductivity through the wick material (e.g., wick material <NUM>) based on the measured impedance.

The impedance measurement may take the form of an electrical pulse (e.g., voltage pulse and measurement of current), or an alternating current (AC) signal at either a single frequency or multiple frequencies (e.g., using impedance spectroscopy). The electrolyte content monitoring circuitry <NUM> may measure impedance between an auxiliary electrode (e.g., auxiliary electrode <NUM> or connecting wire <NUM>) and a counter electrode (e.g., counter electrode <NUM>). The electrolyte content monitoring circuitry <NUM> may measure impedance between two auxiliary electrodes (e.g., auxiliary electrodes <NUM> and <NUM>, or connecting wires <NUM> and <NUM>). The electrolyte content monitoring circuitry <NUM> may measure impedance between other pairs of electrodes. For example, the electrolyte content monitoring circuitry <NUM> may measure impedance across the separator material (e.g., the separator material <NUM>) by, in some instances, measuring the impedance between the first electrode (e.g., the sensing electrode <NUM>) and the second electrode (e.g., the reference electrode <NUM>). Subsequently, the electrolyte content monitoring circuitry <NUM> may use the ratio of the impedance across the wick material (e.g. the wick material <NUM>) to the impedance across the separator material (e.g., the separator material <NUM>) to compensate for changes in electrolyte impedance due to temperature.

The electrolyte content monitoring circuitry <NUM> may be in communication with the third electrode (e.g., counter electrode <NUM>) and the fourth electrode (e.g., auxiliary electrode <NUM>, connecting wire <NUM>). The electrolyte content monitoring circuitry may configured to: measure an impedance between the fourth electrode (e.g., auxiliary electrode <NUM>, connecting wire <NUM>) and the third electrode (e.g., counter electrode <NUM>); and measure an electrical conductivity through the wick material (e.g., wick material <NUM>) based on the measured impedance.

The electrolyte content monitoring circuitry <NUM> may be in communication with the fourth electrode (e.g., auxiliary electrode <NUM>, connecting wire <NUM>) and the fifth electrode (e.g., auxiliary electrode <NUM>, connecting wire <NUM>). The electrolyte content monitoring circuitry may be configured to: measure an impedance between the fourth electrode (e.g., auxiliary electrode <NUM>, connecting wire <NUM>) and the fifth electrode (e.g., auxiliary electrode <NUM>, connecting wire <NUM>); and measure an electrical conductivity through the wick material based on the measured impedance.

The electrolyte content monitoring circuitry <NUM> may be in communication with a first electrode (e.g., counter electrode <NUM>, auxiliary electrode <NUM>, or connecting wire <NUM>) and a second electrode (e.g., auxiliary electrode <NUM> or connecting wire <NUM>). The electrolyte content monitoring circuitry <NUM> may be configured to measure an impedance between the second electrode and the first electrode. The electrolyte content monitoring circuitry may be further configured to measure an electrical conductivity through the wick material based on the measured impedance.

The electrolyte content monitoring circuitry <NUM> may be configured to perform a conductivity measurement across the wick material using a Reflex or Capa type pulse test. The electrolyte content monitoring circuitry <NUM> may be configured to perform a conductivity measurement across the wick material using single or multiple frequency impedance spectroscopy. This conductivity measurement will allow the electrolyte content monitoring circuitry <NUM> to monitor the drying of the wick material and the low electrolyte content detection circuitry <NUM> provide advance warning of impending failure, since the wick material will dry out before the one or more separators. In some instances, the conductivity measurement may comprise some variation in conductivity as the wick becomes relatively dry and percolation effects result in an increasing impedance.

The low electrolyte content detection circuitry <NUM> includes hardware components designed or configured to receive, process, generate, and transmit data, such as electrolyte content monitoring signals. In some embodiments, the low electrolyte content detection circuitry <NUM> may analyze the electrochemical gas monitoring signal to determine that the electrolyte content in the wicking material has fallen below a predetermined electrolyte content level. For example, the low electrolyte content detection circuitry <NUM> may generate a root mean square (RMS) electrolyte content monitoring signal based on the electrolyte content monitoring signal received from the electrolyte content monitoring circuitry <NUM>. The low electrolyte content detection circuitry <NUM> may detect low electrolyte content when the RMS electrolyte content monitoring signal falls below a predetermined electrolyte content monitoring threshold value. In response to detecting the presence of the low electrolyte content, the low electrolyte content detection circuitry <NUM> may generate a low electrolyte content alert signal and transmit the electrochemical gas alert signal to the input-output circuitry <NUM>, the communications circuitry <NUM>, or both for alerting a user or a system that the electrolyte content in the electrochemical gas sensor is low and thus the electrolyte should be replenished or the electrochemical gas sensor should be replaced.

The user interface circuitry <NUM> includes hardware components designed or configured to receive, process, generate, and transmit data, such as user interface data. In some embodiments, the user interface circuitry <NUM> may be configured to generate user interface data indicative of a set of monitoring modes for a particular gas type or environment, electrochemical gas monitoring signals, RMS electrochemical gas monitoring signals, predetermined electrochemical gas monitoring threshold value (e.g., settable by a user using input-output circuitry <NUM> or a user device in communication with input-output circuitry <NUM>; settable by accessing a table of predetermined electrochemical gas monitoring threshold values for various gas types), electrochemical gas alert signals, electrolyte content monitoring signals, RMS electrolyte content monitoring signals, electrolyte content values (including, but not limited to, electrolyte content percentage values), low electrolyte alert signals, and combinations thereof. In some instances, the user interface data may comprise a list (e.g., a selectable drop-down list, a ordered grouping of selectable icons (e.g., clickable icons configured to be clicked by a mouse; virtual icons configured to be displayed on a touchscreen and pressed by a user's finger), a text-based prompt, a voice-based prompt) of monitoring modes. For instance, the user interface circuitry <NUM> may include hardware components designed or configured to generate the user interface data based on any embodiment or combination of embodiments described with reference to <FIG>.

In some embodiments, the user interface circuitry <NUM> may be in communication with a display device (e.g., input-output circuitry <NUM>, a user device, or a display device communicatively coupled thereto) and thus configured to transmit the user interface data to the display device. For example, the user interface circuitry <NUM> may be configured to generate user interface data and transmit the generated user interface data to the input-output circuitry <NUM>, and the input-output circuitry <NUM> may be configured to receive the user interface data and display the received user interface data on one or more display screens.

In some embodiments, each of the electrochemical gas monitoring circuitry <NUM>, electrochemical gas detection circuitry <NUM>, electrolyte content monitoring circuitry <NUM>, low electrolyte content detection circuitry <NUM>, and user interface circuitry <NUM> may include a separate processor, specially configured field programmable gate array (FPGA), application specific interface circuit (ASIC), or cloud utility to perform the above functions. In some embodiments, the hardware components described above with reference to electrochemical gas monitoring circuitry <NUM>, electrochemical gas detection circuitry <NUM>, electrolyte content monitoring circuitry <NUM>, low electrolyte content detection circuitry <NUM>, and user interface circuitry <NUM>, may, for instance, utilize communications circuitry <NUM> or any suitable wired or wireless communications path to communicate with a user device, each other, or any other suitable circuitry or device.

In some embodiments, one or more of the electrochemical gas monitoring circuitry <NUM>, electrochemical gas detection circuitry <NUM>, electrolyte content monitoring circuitry <NUM>, low electrolyte content detection circuitry <NUM>, and user interface circuitry <NUM> may be hosted locally by the apparatus <NUM>. In some embodiments, one or more of the electrochemical gas monitoring circuitry <NUM>, electrochemical gas detection circuitry <NUM>, electrolyte content monitoring circuitry <NUM>, low electrolyte content detection circuitry <NUM>, and user interface circuitry <NUM> may be hosted remotely (e.g., by one or more cloud servers) and thus need not physically reside on the apparatus <NUM>. Thus, some or all of the functionality described herein may be provided by a remote circuitry. For example, the apparatus <NUM> may access one or more remote circuitries via any sort of networked connection that facilitates transmission of data and electronic information between the apparatus <NUM> and the remote circuitries. In turn, the apparatus <NUM> may be in remote communication with one or more of the electrochemical gas monitoring circuitry <NUM>, electrochemical gas detection circuitry <NUM>, electrolyte content monitoring circuitry <NUM>, low electrolyte content detection circuitry <NUM>, and user interface circuitry <NUM>.

As described above and as will be appreciated based on this disclosure, embodiments of the present disclosure may be configured as systems, apparatuses, methods, mobile devices, backend network devices, computer program products, other suitable devices, and combinations thereof. Accordingly, embodiments may comprise various means including entirely of hardware or any combination of software with hardware. Furthermore, embodiments may take the form of a computer program product on at least one non-transitory computer-readable storage medium having computer-readable program instructions (e.g., computer software) embodied in the storage medium. Any suitable computer-readable storage medium may be utilized including non-transitory hard disks, CD-ROMs, flash memory, optical storage devices, or magnetic storage devices. As will be appreciated, any computer program instructions and/or other type of code described herein may be loaded onto a computer, processor or other programmable apparatus's circuitry to produce a machine, such that the computer, processor, or other programmable circuitry that executes the code on the machine creates the means for implementing various functions, including those described herein.

The user device may be embodied by one or more computing devices or systems that also may include processing circuitry, memory, input-output circuitry, and communications circuitry. For example, a user device may be a laptop computer on which an app (e.g., a GUI application) is running or otherwise being executed by processing circuitry. In yet another example, a user device may be a smartphone on which an app (e.g., a webpage browsing app) is running or otherwise being executed by processing circuitry. As it relates to operations described in the present disclosure, the functioning of these devices may utilize components similar to the similarly named components described above with respect to <FIG>. Additional description of the mechanics of these components is omitted for the sake of brevity. These device elements, operating together, provide the respective computing systems with the functionality necessary to facilitate the communication of data with the example electrochemical gas sensor described herein.

Having described specific components and structures of example devices involved in the present disclosure, example procedures for providing an electrochemical gas sensor configured to measure electrolyte content are described below in connection with <FIG>.

<FIG> illustrates a flowchart <NUM> that contains example operations for providing an electrochemical gas sensor configured to measure electrolyte content.

As shown by operation <NUM>, the flowchart <NUM> begins by providing a separator material (e.g., separator material <NUM>) comprising a separator material top surface and a separator material bottom surface opposite the separator material top surface.

As shown by operation <NUM>, the flowchart <NUM> proceeds to disposing a first electrode (e.g., sensing electrode <NUM>) on the separator material top surface.

As shown by operation <NUM>, the example flowchart <NUM> proceeds to disposing a second electrode (e.g., reference electrode <NUM>) on the separator material bottom surface.

As shown by operation <NUM>, the example flowchart <NUM> proceeds to providing a wick material (e.g., wick material <NUM>) comprising a wick material top surface and a wick material bottom surface opposite the wick material top surface.

As shown by operation <NUM>, the example flowchart <NUM> proceeds to providing a third electrode (e.g., counter electrode <NUM>) facing the wick material top surface.

As shown by operation <NUM>, the example flowchart <NUM> proceeds to disposing a fourth electrode (e.g., auxiliary electrode <NUM>, connecting wire <NUM>) on the wick material bottom surface.

Optionally (not shown in <FIG>), the separator material may be a first separator material, the separator material top surface may be a first separator material top surface, and the separator material bottom surface may be a first separator material bottom surface. Optionally, the example flowchart <NUM> may proceed to providing a second separator material (e.g., separator material <NUM>) comprising a second separator material top surface and a second separator material bottom surface opposite the second separator material top surface. Optionally, the example flowchart <NUM> may proceed to disposing the third electrode on the second separator material top surface. Optionally, the example flowchart <NUM> may proceed to disposing the second separator material bottom surface on the wick material top surface.

In some embodiments, operations <NUM>, <NUM>, <NUM>, and <NUM>, <NUM>, and <NUM> may not necessarily occur in the order depicted in <FIG>. In some embodiments, one or more of the operations depicted in <FIG> may occur substantially simultaneously. In some embodiments, one or more additional operations may be involved before, after, or between any of the operations shown in <FIG>. According to the present invention, the method for manufacturing an apparatus for measuring electrolyte content in an electrochemical gas sensor is defined in the appended claim <NUM>.

As described above, <FIG> illustrates an example flowchart describing operations performed in accordance with example embodiments of the present disclosure. It will be understood that each block of the flowchart, and combinations of blocks in the flowchart, may be implemented by various means, such as devices comprising hardware, firmware, one or more processors, and/or circuitry associated with execution of software comprising one or more computer program instructions. For example, one or more of the procedures described above may be performed by material handling equipment (e.g., a robotic arm, servo motor, motion controllers, and the like) and computer program instructions residing on a non-transitory computer-readable storage memory. In this regard, the computer program instructions which embody the procedures described above may be stored by a memory of an apparatus employing an embodiment of the present disclosure and executed by a processor of the apparatus. As will be appreciated, any such computer program instructions may be loaded onto a computer or other programmable apparatus (e.g., hardware) to produce a machine, such that the resulting computer or other programmable apparatus provides for implementation of the functions specified in the flowchart blocks. When executed, the instructions stored in the computer-readable storage memory produce an article of manufacture configured to implement the various functions specified in flowchart blocks. Moreover, execution of a computer or other processing circuitry to perform various functions converts the computer or other processing circuitry into a particular machine configured to perform an example embodiment of the present disclosure.

Accordingly, the described flowchart blocks support combinations of means for performing the specified functions and combinations of operations for performing the specified functions. It will also be understood that one or more flowchart blocks, and combinations of flowchart blocks, can be implemented by special purpose hardware-based computer systems which perform the specified functions, or combinations of special purpose hardware that execute computer instructions.

Words such as "thereafter," "then," "next," and similar words are not intended to limit the order of the steps; these words are simply used to guide the reader through the description of the methods. Further, any reference to claim elements in the singular, for example, using the articles "a," "an" or "the," is not to be construed as limiting the element to the singular and may, in some instances, be construed in the plural.

As described above and with reference to <FIG>, example embodiments of the present disclosure thus provide for an electrochemical gas sensor configured to measure electrolyte content, monitor the drying of the wick material, and provide advance warning of impending failure, since the wick material may dry out before the one or more separators. Thus, the electrochemical gas sensor disclosed herein may easily and cost-effectively meet all of the performance requirements and also be sufficiently sensitive to detect failure and provide advance warning of impending failure, prediction of remaining life, or both.

While various embodiments in accordance with the principles disclosed herein have been shown and described above, modifications thereof may be made by one skilled in the art without departing from the teachings of the disclosure. The embodiments described herein are representative only and are not intended to be limiting. Many variations, combinations, and modifications are possible and are within the scope of the appended claims. Alternative embodiments that result from combining, integrating, and/or omitting features of the embodiment(s) are also within the scope of the appended claims. Accordingly, the scope of protection is not limited by the description set out above, but is defined by the claims which follow.

Furthermore, any advantages and features described above may relate to specific embodiments, but shall not limit the application of such issued claims to processes and structures accomplishing any or all of the above advantages or having any or all of the above features.

Also, techniques, systems, subsystems, and methods described and illustrated in the various embodiments as discrete or separate may be combined or integrated with other systems, modules, techniques, or methods without departing from the scope of the appended claims. Other devices or components shown or discussed as coupled to, or in communication with, each other may be indirectly coupled through some intermediate device or component, whether electrically, mechanically, or otherwise. Other examples of changes, substitutions, and alterations are ascertainable by one skilled in the art and could be made without departing from the scope of the appended claims.

Claim 1:
A system for measuring electrolyte content in an electrochemical gas sensor (<NUM>), the system comprising:
a housing (<NUM>), in which there is disposed:
a separator material (<NUM>) comprising a first separator material surface and a second separator material surface opposite the first separator material surface;
a first electrode (<NUM>) disposed on the first separator material surface;
a second electrode (<NUM>) disposed on the second separator material surface;
a wick material (<NUM>) comprising a first wick material surface and a second wick material surface opposite the first wick material surface;
a liquid electrolyte disposed at least in the wick material (<NUM>) and the separator material (<NUM>);
a third electrode (<NUM>) disposed on the first wick material surface;
a porous polytetrafluoroethylene, PTFE, film tape (<NUM>) to support and electrically separate the second electrode (<NUM>) and the third electrode (<NUM>); and
a fourth electrode (<NUM>, <NUM>) disposed on the second wick material surface, wherein the fourth electrode (<NUM>, <NUM>) is configured to measure an electrical conductivity through the wick material (<NUM>),
wherein the separator material (<NUM>) comprises a first hydrophilic material, wherein the wick material (<NUM>) comprises a second hydrophilic material, and wherein the first hydrophilic material is more hydrophilic than the second hydrophilic material.