# US 12,000,721 B2 · Air duct airflow sensor with internal low-pressure detector > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,000,721 B2 - Document ID: US12000721B2 - Status: Granted - Kind: B2 - Application number: 16/993,812 - Filed: 2020-08-14 - Published: 2020-11-26 - Granted: 2024-06-04 - Earliest claimed: 2018-01-17 - Assignees: Tyco Fire & Security GmbH - Applicants: Johnson Controls Tyco IP Holdings LLP - Inventors: Jean H. Scholten - Web page: https://patentgrep.com/patent/US12000721B2 ## CPC - G01F 1/40: Details of construction of the flow constriction devices - F24F 11/30: for purposes related to the operation of the system, e.g. for safety or monitoring - F24F 11/49: ensuring correct operation, e.g. by trial operation or configuration checks - F24F 11/74: for controlling air flow rate or air velocity - F24F 13/10: movable, e.g. dampers - G01F 5/00: Measuring a proportion of the volume flow - G05D 7/00: Control of flow (level control G05D9/00; control of flow ratio G05D11/00) - F24F 2110/40: Pressure, e.g. wind pressure - G01F 1/684: Structural arrangements; Mounting of elements, e.g. in relation to fluid flow - G01F: MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME - F24F: AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING (removing dirt or fumes from areas where they are produced B08B15/00; vertical ducts for carrying away waste gases from buildings E04F17/02; tops for chimneys or ventilating shafts, terminals for flues F23L17/02) - G05D: SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES ## Abstract An airflow sensor assembly for an air duct is provided. The airflow sensor assembly includes an air duct having an interior wall and an exterior wall, a high pressure detection device, and a low pressure detection device. The low pressure detection device includes a hollow ring disposed within the interior wall of the air duct. The hollow ring includes an inner periphery portion, an outer periphery portion, and a first set of apertures defined therein. The first set of apertures is spaced around the inner periphery portion of the hollow ring. The airflow sensor assembly further includes a pressure sensor fluidly coupled to the high pressure detection device and the low pressure detection device. ## Claims ### Claim 1 An airflow sensor assembly for an air duct, the air duct having an interior and comprising: a high pressure detection component; a low pressure detection component, comprising: a surface to be disposed within the interior of the air duct and having geometry to provide an air restriction in the interior of the air duct, the surface having a plurality of first apertures spaced along the surface; and a pressure sensor system configured to be fluidly coupled to the high pressure detection component and the low pressure detection component. ### Claim 2 (depends on 1) The airflow sensor assembly for an air duct of claim 1, wherein the surface defines a portion of an inner surface of a wall of the air duct and the pressure sensor system comprises a first sensor coupled to the high pressure component and a second sensor coupled to the low pressure component. ### Claim 3 (depends on 2) The airflow sensor assembly of claim 2, wherein the high pressure detection component comprises: a first gasket having a recessed area defined therein and a first connecting opening, the first gasket being fitted over an exterior surface of the wall and proximate second apertures in the wall of the air duct, the second apertures upstream of the first apertures; and a first tube fluidly coupled to the first connecting opening. ### Claim 4 (depends on 2) The airflow sensor assembly of claim 2, wherein the low pressure detection component comprises: a first gasket having a first connecting opening, the first gasket being fitted over an exterior surface of the wall and forming a chamber between the first gasket and the exterior surface of the wall with which the first apertures fluidly couple; and a first tube fluidly coupled to the first connecting opening. ### Claim 5 (depends on 3) The airflow sensor assembly of claim 3, wherein the low pressure detection component comprises: a second gasket and a second connecting opening, the second gasket being fitted over the exterior surface of the wall and forming a chamber between the second gasket and the exterior surface of the wall with which the first apertures fluidly couple; and a second tube fluidly coupled to the second connecting opening, the second connecting opening being fluidly coupled to the chamber. ### Claim 6 (depends on 5) The airflow sensor assembly of claim 5, wherein the pressure sensor system is fluidly coupled to the first tube and the second tube. ### Claim 7 (depends on 3) The airflow sensor assembly of claim 3, further comprising a gasket guard ring configured to fit over an exterior surface of the first gasket. ### Claim 8 (depends on 1) The airflow sensor assembly of claim 1, wherein the surface is part of a wall of the air duct and has a portion with a U shaped cross section, the portion providing the air restriction, wherein the pressure sensor system comprises a first sensor coupled to the high pressure component and the low pressure component. ### Claim 9 (depends on 8) The airflow sensor assembly of claim 8, wherein the first apertures are provide in the portion at a bottom of the u shaped cross section. ### Claim 10 (depends on 1) The airflow sensor assembly of claim 1, wherein the surface is part of a wall of the air duct and has a portion forming a channel feature providing the air restriction, the channel feature having a depth from 0.5 inches to 0.75 inches. ### Claim 11 An airflow sensor assembly for an air duct, the air duct having an interior wall and an exterior wall; comprising: a first pressure structure; a second pressure structure, comprising: an airflow restriction surface; and a plurality of first apertures defined at the airflow restriction surface and spaced around a periphery of the air duct; a first gasket having a first connecting opening, the first gasket being fitted over the exterior wall and proximate the first apertures and the first gasket and the airflow restriction surface being configured to define a chamber; and either (a) at least one pressure sensor configured to be fluidly coupled to both the first pressure structure and the second pressure structure or (b) a first pressure sensor configured to be fluidly coupled to the first pressure structure and a second pressure sensor configured to be fluidly coupled to the second pressure structure. ### Claim 12 (depends on 11) The airflow sensor assembly of claim 11, wherein the airflow restriction surface is formed from a U shaped indent in the exterior wall. ### Claim 13 (depends on 11) The airflow sensor assembly of claim 11, wherein the first pressure structure comprises: second apertures defined in the exterior wall; a second gasket having a recessed area defined therein and a second connecting opening, the second gasket being fitted over the exterior wall and proximate the second plurality of apertures; and a second tube fluidly coupled to the second connecting opening. ### Claim 14 (depends on 13) The airflow sensor assembly of claim 13, wherein the at least one pressure sensor that is configured to be fluidly coupled to both the first pressure structure and the second pressure structure is fluidly coupled to a first tube fluidly coupled to the chamber and the second tube. ### Claim 15 (depends on 14) The airflow sensor assembly of claim 14, further comprising a plurality of gasket guard rings configured to fit over at least one of an exterior surface of the first gasket or an exterior surface of the second gasket. ### Claim 16 (depends on 11) The airflow sensor assembly of claim 11, further comprising a damper control assembly communicably coupled to the at least one pressure sensor configured to be fluidly coupled to both the first pressure structure and the second pressure structure. ### Claim 17 (depends on 16) The airflow sensor assembly of claim 16, wherein the damper control assembly comprises an air damper assembly, a motor, and an actuator. ### Claim 18 A method of sensing airflow in an air duct, the method comprising: receiving a first air pressure measurement from a first pressure detection structure; receiving a second air pressure measurement from a second pressure detection structure, the second pressure detection structure comprising: a restrictive portion disposed within an interior wall of the air duct, the restrictive portion having first apertures defined therein; and a first tube fluidly coupled to a first connecting opening in communication with a chamber at least partially defined by the restrictive portion; and calculating an air velocity through the air duct based on the first air pressure measurement and the second air pressure measurement. ### Claim 19 (depends on 18) The method of claim 18, wherein the first pressure detection structure comprises: a gasket having a recessed area defined therein and a second connecting opening, the gasket being fitted over an exterior wall of the air duct and proximate second apertures in the air duct; and a second tube fluidly coupled to the second connecting opening. ### Claim 20 (depends on 18) The method of claim 18, wherein each of the first apertures are orthogonal to a direction of airflow through the air duct.