# US 10,502,710 B2 · Particulate matter measurement apparatus and method > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,502,710 B2 - Document ID: US10502710B2 - Status: Granted - Kind: B2 - Application number: 15/614,992 - Filed: 2017-06-06 - Published: 2017-12-07 - Granted: 2019-12-10 - Earliest claimed: 2016-06-06 - Assignees: AlphaSense Oy; Cambridge Enterprise Limited - Applicants: Cambridge Enterprise Limited; Alphasense, Limited - Inventors: Simone Hochgreb; Robert Nishida; Adam Boies; John Saffell - Web page: https://patentgrep.com/patent/US10502710B2 ## CPC - G01N 27/70: and measuring current or voltage - B03C 3/017: Combinations of electrostatic separation with other processes, not otherwise provided for - B03C 3/025: {Combinations of electrostatic separators, e.g. in parallel or in series, stacked separators or dry-wet separator combinations} - B03C 3/383: {using radiation} - B03C 3/47: flat, e.g. plates, discs, gratings - B03C 3/49: tubular - G01N 15/0266: {with electrical classification} - G01N 15/0656: {using electric, e.g. electrostatic methods or magnetic methods (by investigating individual particles G01N15/1031, G01N15/12)} - G01N 15/1031: by measuring electrical or magnetic effects - G01N 27/66: and measuring current or voltage - G01N 15/0606: {by collecting particles on a support} - 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) - B03C: MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS (separating isotopes B01D59/00; combinations of magnetic or electrostatic separation with separation of solids by other means B03B, B07B) ## Abstract Particle measurement apparatus comprises an inlet for receiving a gas sample for analysis, a photoionisation chamber, at least one light source arranged to illuminate an interior of the photoionisation chamber, first and second electrodes coupled to a power source and configured to provide a DC potential difference across at least a portion of the photoionisation chamber, and an outlet, together defining a gas flow path from the inlet, through the photoionisation chamber, and towards the outlet. ## Claims ### Claim 1 Particulate matter measurement apparatus comprising an inlet for receiving a gas sample for analysis, a photoionisation chamber, at least one light source arranged to illuminate an interior of the photoionisation chamber to photoionize particulate matter in the gas sample, first and second electrodes coupled to a power source and configured to provide a DC potential difference across at least a portion of the photoionisation chamber, and an outlet, together defining a gas flow path from the inlet, through the photoionisation chamber, and towards the outlet. ### Claim 2 (depends on 1) The apparatus of claim 1 further comprising at least one electrode current sensor configured to measure an electrode current flowing to or from at least one of the first and second electrodes. ### Claim 3 (depends on 2) The apparatus according to claim 2 further comprising a charged particulate matter detector and at least one detector current sensor configured to measure a detector current flowing from the charged particulate matter detector. ### Claim 4 (depends on 3) The apparatus according to claim 3 further comprising a comparator circuit configured to compare the electrode current, measured by the at least one electrode current sensor, and the detector current, measured by the at least one detector current sensor. ### Claim 5 (depends on 3) The apparatus according to claim 3 further comprising a processor configured to process the electrode current, measured by the at least one electrode current sensor, and the detector current, measured by the at least one detector current sensor, to determine a particulate matter concentration and/or size parameter of the particulate matter. ### Claim 6 (depends on 3) The apparatus of claim 3, further comprise a comparator circuit is configured to compare the electrode current, measured by the at least one electrode current sensor, and the detector current, measured by the at least one detector current sensor to determine a particulate matter concentration and/or size parameter of the particulate matter. ### Claim 7 (depends on 1) The apparatus according to claim 1, wherein the potential difference provided by the first and second electrodes is variable between at least first and second different DC voltages. ### Claim 8 (depends on 7) The apparatus according to claim 7, wherein the potential difference provided by the first and second electrodes is maintainable at each of the at least first and second different DC voltages for at least 0.5 seconds. ### Claim 9 (depends on 7) The apparatus according to claim 7, wherein the potential difference provided by the first and second electrodes is variable between the at least first and second different DC voltages at a frequency of less than 2 Hz. ### Claim 10 (depends on 1) The particulate measurement apparatus of claim 1 further comprising: a plurality of additional electrodes coupled to an additional power supply and configured to provide at least an additional potential difference across another portion of the photoionisation chamber concurrently with the potential difference provided across the portion of the photoionisation chamber. ### Claim 11 (depends on 1) The apparatus of claim 1, wherein the light source is an ultraviolet light source configured to emit ultraviolet light. ### Claim 12 (depends on 1) The apparatus of claim 1, wherein the light source is an ultraviolet light source configured to emit ultraviolet light within a range of 150 nm to 260 nm. ### Claim 13 A method of using a particulate matter measurement apparatus, the method comprising: receiving a gas sample for analysis using an inlet, providing a photoionisation chamber, illuminating an interior of the photoionisation chamber using at least one light source to photoionize particulate matter in the gas sample; coupling first and second electrodes to a power source to provide a DC potential difference across at least a portion of the photoionisation chamber, and providing an outlet, together defining a gas flow path from the inlet, through the photoionisation chamber, and towards the outlet. ### Claim 14 (depends on 1) The apparatus of claim 1, wherein the particulate matter is soot particles. ### Claim 15 Particulate matter measurement apparatus comprising an inlet for receiving a gas sample for analysis, a photoionisation chamber, first and second electrodes, at least one light source arranged to illuminate an interior of the photoionisation chamber between the first and second electrodes to photoionize particulate matter in the gas sample, at least one electrode current sensor configured to measure an electrode current flowing to or from at least one of the first and second electrodes, and an outlet, together defining a gas flow path from the inlet, through the photoionisation chamber between the first and second electrodes, and towards the outlet. ### Claim 16 (depends on 13) The method according to claim 13 wherein the light source is an ultraviolet light source configured to emit ultraviolet light within a range of 150 nm to 260 nm. ### Claim 17 (depends on 16) The method of claim 16 applying another potential difference concurrently with the potential difference provided across the portion of the photoionisation chamber, by way of a plurality of additional electrodes, across another portion of the photoionisation chamber through which sample gas flows; and measuring one or more electrode currents flowing to or from at least one electrode from the plurality of additional electrodes. ### Claim 18 (depends on 16) The method of claim 16 further comprising measuring an electrode current flowing to or from at least one of the first and second electrodes using at least one electrode current sensor. ### Claim 19 (depends on 18) The method according to claim 18 further comprising providing a charged particulate matter detector and measuring a detector current flowing from the charged particulate matter detector using at least one detector current sensor. ### Claim 20 (depends on 19) The method according to claim 19 further comprising comparing, using a comparator circuit, the electrode current measured by the at least one electrode current sensor and the detector current measured by the at least one detector current sensor. ### Claim 21 (depends on 20) The method according to claim 20 further comprising using the electrode current measured by the at least one electrode current sensor and the detector current measured by the at least one detector current sensor to determine a particulate matter concentration and/or size parameter of the particulate matter. ### Claim 22 (depends on 19) The method according to claim 19 further comprising processing, using a processor, the electrode current, measured by the at least one electrode current sensor, and the detector current, measured by the at least one detector current sensor, to determine a particulate matter concentration and/or size parameter of the particulate matter. ### Claim 23 (depends on 16) The method according to claim 16, wherein the potential difference provided by the first and second electrodes is variable between at least first and second different DC voltages. ### Claim 24 (depends on 23) The method according to claim 23, wherein the potential difference provided by the first and second electrodes is maintainable at each of the at least first and second different DC voltages for at least 0.5 seconds. ### Claim 25 (depends on 23) The method according to claim 23, wherein the potential difference provided by the first and second electrodes is variable between the at least first and second different DC voltages at a frequency of less than 2 Hz. ### Claim 26 (depends on 16) The method according to claim 16 wherein the light source is an ultraviolet light source configured to emit ultraviolet light. ### Claim 27 (depends on 16) The method according to claim 16 wherein the particulate matter is soot particles.