# US 12,111,335 B2 · Measurement of gas flow rate > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,111,335 B2 - Document ID: US12111335B2 - Status: Granted - Kind: B2 - Application number: 18/296,096 - Filed: 2023-04-05 - Published: 2023-10-12 - Granted: 2024-10-08 - Earliest claimed: 2022-04-06 - Assignees: QLM Technology Ltd - Applicants: QLM Technology Limited - Inventors: Murray Keith Reed; Xiao Ai - Web page: https://patentgrep.com/patent/US12111335B2 ## CPC - G01M 3/202: {using mass spectrometer detection systems} - G01P 5/26: by measuring the direct influence of the streaming fluid on the properties of a detecting optical wave - G01M 3/186: {for containers, e.g. radiators} - G01M 3/22: for pipes, cables or tubes; for pipe joints or seals; for valves; {for welds; for containers, e.g. radiators} - G01P 5/02: by measuring forces exerted by the fluid on solid bodies, e.g. anemometer - G01S 7/4808: {Evaluating distance, position or velocity data} - G01S 17/89: for mapping or imaging - G01S 17/95: for meteorological use - G01M: TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR - G01P: MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT (measuring or recording blood flow A61B5/02, A61B8/06; monitoring speed or deceleration of electrically-propelled vehicles B60L3/00; vehicle lighting systems adapted to indicate speed B60Q1/54; determining position or course in navigation, measuring ground distance in geodesy or surveying G01C; combined measuring devices for measuring two or more variables of movement G01C23/00; measuring velocity of sound G01H; measuring velocity of light G01J7/00; measuring direction or velocity of solid objects by reception or emission of radiowaves or other waves and based on propagation effects, e.g. Doppler effect, propagation time, direction of propagation, G01S; measuring speed of nuclear radiation G01T; measuring acceleration of gravity G01V; {measuring or recording the speed of trains B61L23/00; speed indicators incorporated in motor vehicles B60K35/00; measuring frequency or phase G01R; traffic control G08G}) - G01S: RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES ## Abstract Methods and apparatus for detecting and measuring gas flow are disclosed in which lidar distance information, acquired during the detection of gas using a lidar sensor, is used together with prevailing wind data to determine local wind data for the leak location. This local wind data, which may comprise one or more vectors or a 3D wind model, is used in the determination of flow rate. ## Claims ### Claim 1 A method of detecting and measuring a gas flow, the method comprising: receiving gas detection data from a field of view of a lidar sensor; receiving distance information relating to solid structures in the field of view; using the distance information to obtain 3D structure information relating to the solid structures; determining a location of the detected gas; receiving prevailing wind data for the location of the detected gas; determining local wind data for the location of the detected gas based on the prevailing wind data and the distance information; determining the rate of flow of the gas using the lidar gas detection data and the local wind data; and determining gas concentration pathlengths for points in the field of view based on the gas detection data and the distance information, wherein determining a location of the detected gas comprises determining a location of a source of the detected gas, and wherein the location of the source of the detected gas is determined from the gas concentration pathlengths, and wherein determining the location of the source of the detected gas comprises identifying an area of the field of view in which a gas concentration pathlength exceeds a threshold, and wherein determining the location of the source of the detected gas comprises determining the location of the source of the detected gas from the sensor location and determining the lidar range from the sensor to the area. ### Claim 2 (depends on 1) The method of claim 1, comprising: using the lidar sensor to obtain the gas detection data and the distance information. ### Claim 3 (depends on 1) The method of claim 1, comprising: using the distance information and the prevailing wind data to identify objects in the field of view obstructing the flow of the gas, wherein determining the local wind data comprises modifying the prevailing wind data to account for the identified objects. ### Claim 4 (depends on 3) The method of claim 3, wherein the distance information is combined with the prevailing wind data and a computational flow dynamics model to predict local wind data for use in the determination of the rate of flow of the gas. ### Claim 5 (depends on 1) The method of claim 1, wherein the local wind data is determined by attenuating one or more components of the prevailing wind data perpendicular to a surface of a structure. ### Claim 6 The method ofclaim 1, wherein obtaining the gas detection data and obtaining the distance information are repeated in successive data acquisition periods, wherein the local wind data is determined at multiple instances during a data acquisition period, and wherein the local wind data determined at multiple instances during a data acquisition period is used to determine constant local wind data for the acquisition period. ### Claim 7 (depends on 1) The method of claim 1, comprising: determining gas concentration pathlengths for points in the field of view based on the gas detection data and the distance information, wherein determining the rate of flow of the gas comprises multiplying a gas concentration path length by the local wind data, and wherein the rate of flow of the gas is determined using only gas concentration path length measurements obtained when the local wind data satisfies predetermined criteria. ### Claim 8 (depends on 1) The method of claim 1, wherein the lidar sensor is scanned over the field of view during a data acquisition period, and wherein for different points in the field of view multiple gas concentration measurements are obtained. ### Claim 9 (depends on 1) The method of claim 1, wherein determining a location of the detected gas comprises determining a location of a source of the detected gas. ### Claim 10 (depends on 1) The method of claim 1, wherein the determining the location of the source of the detected gas comprises overlaying a gas concentration pathlength image over a signal level image to indicate the location of the gas leak. ### Claim 11 (depends on 1) The method of claim 1, wherein the distance information is used to create a 3D map of structures in the field of view and wherein the 3D map is used in determining the local wind data. ### Claim 12 (depends on 1) The method of claim 1, wherein the prevailing wind data is acquired using an anemometer, and wherein the anemometer is co-located with the lidar sensor.