# US 2021/0172901 A1 · Electrochemical gas sensor assembly > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2021/0172901 A1 - Document ID: US20210172901A1 - Status: Published application - Kind: A1 - Application number: 17/247,125 - Filed: 2020-12-01 - Published: 2021-06-10 - Earliest claimed: 2019-12-05 - Assignees: RAE Systems, Inc. - Applicants: RAE Systems, Inc. - Inventors: Qinghui MU; Jianglin JIAN; Feng LIANG; Ling LIU; Na WEI - Web page: https://patentgrep.com/patent/US20210172901A1 ## CPC - G01N 27/4045: {for gases other than oxygen} - G01N 27/404: Cells with anode, cathode and cell electrolyte on the same side of a permeable membrane which separates them from the sample fluid {, e.g. Clark-type oxygen sensors} - G01N 33/0059: {Avoiding interference of a gas with the gas to be measured} - B01D 2253/102: Carbon - G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q) - B01D: SEPARATION (separating solids from solids by wet methods B03B, B03D; by pneumatic jigs or tables B03B; by other dry methods B07; magnetic or electrostatic separation of solid materials from solid materials or fluids, separation by high-voltage electric fields B03C; centrifuges, vortex apparatus B04; presses per se for squeezing-out liquid from liquid-containing material B30B9/02; treatment of water C02F, e.g. softening by ion-exchange C02F1/42; {arrangements of air intake cleaners in gas turbine plants F02C7/05} ; arrangements or mounting of filters in air-conditioning, air-humidification or ventilation F24F13/28) ## Abstract Various example embodiments described herein relate to a sensor assembly. The sensor assembly includes a first sensor cover and a second sensor cover. The first sensor cover is disposed on a first end of the sensor assembly and the second sensor cover is disposed on a second end of the sensor assembly. The first sensor cover defines a first capillary and the second sensor cover defines a second capillary therethrough. The sensor assembly further includes a first sensing unit, a second sensing unit, and a filter. The first sensing unit and the second sensing unit are disposed between the first sensor cover and the second sensor cover. In some example embodiments, the filter is reactive to a target gas and thereby prevents an inflow of the target gas through the second capillary into the sensor assembly. ## Claims ### Claim 1 A sensor assembly, comprising: a first sensor cover disposed on a first end of the sensor assembly, the first sensor cover defining a first capillary therethrough; a second sensor cover disposed on a second end of the sensor assembly, the second sensor cover defining a second capillary therethrough; a first sensing unit comprising a sensing electrode disposed on the first end of the sensor assembly; a second sensing unit comprising an auxiliary electrode disposed on the second end of the sensor assembly, wherein each of the sensing electrode and the auxiliary electrode is positioned between the first sensor cover and the second sensor cover; and a filter, disposed on the second capillary and defined by a material reactive to a target gas, wherein the filter is configured to prevent an inflow of the target gas through the second capillary. ### Claim 2 (depends on 1) The sensor assembly of claim 1, wherein the first sensing unit further comprises: a reference electrode; and a counter electrode, wherein the reference electrode and the counter electrode are positioned between the sensing electrode and the auxiliary electrode. ### Claim 3 (depends on 1) The sensor assembly of claim 1, wherein the filter includes at least one of a membrane, a chemical substance, or a mixture of the chemical substance with glass fiber. ### Claim 4 (depends on 3) The sensor assembly of claim 3, wherein the membrane comprises an activated carbon filter. ### Claim 5 (depends on 3) The sensor assembly of claim 3, wherein the chemical substance includes potassium permanganate to absorb volatile organic compounds (VOC) and content of formaldehyde present in the target gas. ### Claim 6 (depends on 1) The sensor assembly of claim 1, further comprising a printed circuit board (PCB) coupled to the sensor assembly, the printed circuit board configured to: determine a first current based on a first reaction between the target gas and the first sensing unit in the presence of at least one environmental parameter; and determine a second current based on a second reaction at the second sensing unit. ### Claim 7 (depends on 6) The sensor assembly of claim 6, wherein the first current corresponds to an amount of the target gas at the first sensing unit and the second current corresponds to a magnitude of the at least one environmental parameter. ### Claim 8 (depends on 7) The sensor assembly of claim 7, wherein the printed circuit board is further configured to determine a differential current based on the first current and the second current, wherein the differential current corresponds to an amount of noise level based on the magnitude of the at least one environmental parameter. ### Claim 9 (depends on 6) The sensor assembly of claim 6, wherein the at least one environmental parameter includes at least one of a temperature value or a humidity value, within the sensor assembly. ### Claim 10 (depends on 1) The sensor assembly of claim 1, wherein the first capillary is configured to allow the inflow of the target gas into the sensor assembly. ### Claim 11 A sensor assembly, comprising: a first sensing unit comprising a sensing electrode; a second sensing unit comprising an auxiliary electrode; a first sensor cover disposed on the auxiliary electrode, the first sensor cover defining a first capillary; wherein the first capillary is laminated with a chemical substance, reactive to a target gas, to prevent an inflow of the target gas through the first capillary; and a second sensor cover disposed on the sensing electrode, the second sensor cover defining a second capillary and permitting the inflow of the target gas therethrough. ### Claim 12 (depends on 11) The sensor assembly of claim 11, wherein the first sensing unit further comprises a reference electrode and a counter electrode, and wherein the reference electrode and the counter electrode are positioned between the sensing electrode and the auxiliary electrode. ### Claim 13 (depends on 11) The sensor assembly of claim 11, wherein the second sensing unit is disposed on a first end of the sensor assembly and the first sensing unit is disposed on a second end of the sensor assembly. ### Claim 14 (depends on 11) The sensor assembly of claim 11, wherein the chemical substance includes at least one of potassium permanganate, or a mixture of glass fiber with potassium permanganate. ### Claim 15 A sensor assembly, comprising: a housing comprising: a first sensor cover, disposed on a first end of the housing, the first sensor cover defining a first capillary which is configured to allow a target gas to pass therethrough; a second sensor cover, disposed on a second end of the housing, the second sensor cover defining a second capillary; a first sensing unit; a second sensing unit, wherein each of the first sensing unit and the second sensing unit is positioned between the first sensor cover and the second sensor cover; and a filter, defined by a material reactive to the target gas, positioned to be in fluidic communication with the second capillary, the filter configured to prevent an inflow of the target gas therethrough. ### Claim 16 (depends on 15) The sensor assembly of claim 15, wherein the first sensing unit comprises: a sensing electrode coupled with the first capillary; a reference electrode; and a counter electrode, and wherein the second sensing unit comprises an auxiliary electrode coupled with the second capillary within the housing, and wherein the reference electrode and the counter electrode are positioned between the sensing electrode and the auxiliary electrode. ### Claim 17 (depends on 15) The sensor assembly of claim 15, wherein the filter includes at least one of a membrane, a chemical substance, and a mixture of chemical substance with glass fiber. ### Claim 18 (depends on 15) The sensor assembly of claim 15, further comprising a printed circuit board configured to: determine a first current based on a first reaction, in the presence of at least one environmental parameter, and determine a second current based on a second reaction at the second sensing unit. ### Claim 19 (depends on 18) The sensor assembly of claim 18, wherein the first current corresponds to an amount of the target gas at the first sensing unit and the second current corresponds to a magnitude of the at least one environmental parameter at the second sensing unit. ### Claim 20 (depends on 18) The sensor assembly of claim 18, wherein the printed circuit board is further configured to determine a differential current based on the first current and the second current, wherein the differential current corresponds to an amount of noise level based on the magnitude of the at least one environmental parameter.