# US 10,481,060 B2 · Density sensor and density sensor manufacturing method > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,481,060 B2 - Document ID: US10481060B2 - Status: Granted - Kind: B2 - Application number: 15/273,014 - Filed: 2016-09-22 - Published: 2017-03-23 - Granted: 2019-11-19 - Earliest claimed: 2015-09-22 - Assignees: Wika Tech - Applicants: Avenisense - Inventors: Francois Chaudoreille; Guillaume Granier; Lucia Jimenez - Web page: https://patentgrep.com/patent/US10481060B2 ## CPC - G01N 9/002: {using variation of the resonant frequency of an element vibrating in contact with the material submitted to analysis (G01N9/34 takes precedence)} - G01D 11/30: Supports specially adapted for an instrument; Supports specially adapted for a set of instruments - G01N 11/16: by measuring damping effect upon oscillatory body - 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) - G01D: MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR ## Abstract A density sensor to measure the density of a gas having a density ranging from 30 gram per cubic meter to 150 kilogram per cubic meter and a working pressure ranging from 0 to 100 bar. The density sensor includes a resonator housing, a membrane, an actuating/detecting module mechanically coupled to the membrane, and a resonating element arranged to be immersed in the gas, the resonating element being mechanically coupled to the membrane by a pedestal. The resonating element is a resonating disk having a thickness ranging from 25 μm to 200 μm and a diameter ranging from 4 mm to 12 mm. The resonating disk extends parallelly to the membrane or being angled relatively to the membrane and is coupled by its center to the pedestal. The resonating disk is made of a metal chosen among the group comprising stainless steel, nickel-iron alloy and Molybdenum. ## Claims ### Claim 1 A density sensor to measure density of a gas having a density ranging from 30 gram per cubic meter to 150 kilogram per cubic meter and a working pressure ranging from 0 to 100 bar comprising: a resonator housing defining a chamber isolated from the gas, the resonator housing comprising an area of reduced thickness defining a membrane separating the chamber from the gas; an actuating/detecting module positioned within the chamber so as to be isolated from the gas and mechanically coupled to the membrane; a resonating element arranged to be immersed in the gas, the resonating element being mechanically coupled to the membrane by a pedestal; wherein the membrane, the pedestal and the resonator housing are made of metal; wherein the membrane has a thickness enabling transfer of mechanical vibration between the actuating/detecting module and the resonating element through the pedestal; wherein the resonating element is a resonating disk having a thickness ranging from 25 μm to 200 μm and a diameter ranging from 4 mm to 12 mm, the resonating disk extending parallelly to the membrane or being angled relatively to the membrane, and being coupled by its center to the pedestal, the resonating disk being made of a metal chosen among a group comprising stainless steel, nickel-iron alloy and Molybdenum; and wherein the resonating disk comprises two opposing major surfaces, one major surface having a thinned or tapered edge forming a shoulder creating a dissymmetry between the two major surfaces such as to generate an anisotropic resonating disk. ### Claim 2 (depends on 1) The density sensor of claim 1, wherein the pedestal has a section diameter of 1 mm. ### Claim 3 (depends on 1) The density sensor of claim 1, wherein the actuating/detecting module comprises a piezoelectric ceramic. ### Claim 4 (depends on 1) The density sensor of claim 1, wherein the membrane and the pedestal are made of a metal chosen among the group comprising stainless steel, nickel-iron alloy and Molybdenum. ### Claim 5 (depends on 1) The density sensor of claim 1, further comprising: an electronics housing defining a second chamber isolated from the gas and comprising an electronic board connected to the actuating/detecting module and to a connector; a supporting and attaching plate to support and couple together the resonator housing and the electronics housing; and means for attaching the density sensor to a wall. ### Claim 6 (depends on 1) The density sensor of claim 1, wherein the resonator housing further comprises a through-hole extending parallel to a longitudinal axis of the resonator housing close to an external circumference of the resonator housing and emerging in a portion of the density sensor arranged to be in contact with the gas to be measured close to the membrane, the through-hole receiving a temperature sensor probe in a sealed manner. ### Claim 7 (depends on 1) The density sensor of claim 1, further comprising a protective cover protecting the membrane, the pedestal and the resonating element against solid particles and/or moisture contained in the gas and letting the gas flow around the resonating element, said protective cover comprising a thin metal mesh coated with a hydrophobic polymer. ### Claim 8 A density sensor to measure density of a gas having a density ranging from 30 gram per cubic meter to 150 kilogram per cubic meter and a working pressure ranging from 0 to 100 bar comprising: a resonator housing defining a chamber isolated from the gas, the resonator housing comprising an area of reduced thickness defining a membrane separating the chamber from the gas; an actuating/detecting module positioned within the chamber so as to be isolated from the gas and mechanically coupled to the membrane; a resonating element arranged to be immersed in the gas, the resonating element being mechanically coupled to the membrane by a pedestal; wherein the membrane, the pedestal and the resonator housing are made of metal; wherein the membrane has a thickness enabling transfer of mechanical vibration between the actuating/detecting module and the resonating element through the pedestal; wherein the resonating element is a resonating disk having a thickness ranging from 25 μm to 200 μm and a diameter ranging from 4 mm to 12 mm, the resonating disk extending parallelly to the membrane or being angled relatively to the membrane, and being coupled by its center to the pedestal, the resonating disk being made of a metal chosen among a group comprising stainless steel, nickel-iron alloy and Molybdenum; and wherein the resonating disk comprises two opposing major surfaces, one major surface having at least one undulation creating a dissymmetry between the two major surfaces such as to generate an anisotropic resonating disk. ### Claim 9 A method of using a density sensor to measure density of a gas having a density ranging from 30 gram per cubic meter to 150 kilogram per cubic meter and a working pressure ranging from 0 to 100 bar within a tubing or a container comprising: tightly coupling the density sensor to a wall of the tubing or the container, or immersing the density sensor into a first chamber, said density sensor comprising: a resonator housing defining a second chamber isolated from the gas, the resonator housing comprising an area of reduced thickness defining a membrane separating the second chamber from the gas; an actuating/detecting module positioned within the second chamber so as to be isolated from the gas and mechanically coupled to the membrane; a resonating element arranged to be immersed in the gas, the resonating element being mechanically coupled to the membrane by a pedestal; wherein the membrane, the pedestal and the resonator housing are made of metal; wherein the membrane has a thickness enabling transfer of mechanical vibration between the actuating/detecting module and the resonating element through the pedestal; wherein the resonating element is a resonating disk having a thickness ranging from 25 μm to 200 μm and a diameter ranging from 4 mm to 12 mm, the resonating disk extending parallelly to the membrane or being angled relatively to the membrane, and being coupled by its center to the pedestal, the resonating disk being made of a metal chosen among a group comprising stainless steel, nickel-iron alloy and Molybdenum; and wherein the resonating disk comprises two opposing major surfaces, one major surface having a thinned or tapered edge forming a shoulder creating a dissymmetry between the two major surfaces such as to generate an anisotropic resonating disk; the method further comprising: immersing the resonating element into the gas; transferring mechanical vibration from the actuating/detecting module through the membrane to the resonator via the pedestal; measuring by the actuating/detecting module a signal representative of the vibration of the resonating element; and amplifying and processing the signal representative of the vibration of the resonating element by: determining a resonance frequency; and determining the density of the gas by comparing the resonance frequency to calibration measurements. ### Claim 10 A method of using a density sensor to measure density of a gas having a density ranging from 30 gram per cubic meter to 150 kilogram per cubic meter and a working pressure ranging from 0 to 100 bar within a tubing or a container comprising: tightly coupling the density sensor to a wall of the tubing or the container, or immersing the density sensor into a first chamber, said density sensor comprising: a resonator housing defining a second chamber isolated from the gas, the resonator housing comprising an area of reduced thickness defining a membrane separating the second chamber from the gas; an actuating/detecting module positioned within the second chamber so as to be isolated from the gas and mechanically coupled to the membrane; a resonating element arranged to be immersed in the gas, the resonating element being mechanically coupled to the membrane by a pedestal; wherein the membrane, the pedestal and the resonator housing are made of metal; wherein the membrane has a thickness enabling transfer of mechanical vibration between the actuating/detecting module and the resonating element through the pedestal; wherein the resonating element is a resonating disk having a thickness ranging from 25 μm to 200 μm and a diameter ranging from 4 mm to 12 mm, the resonating disk extending parallelly to the membrane or being angled relatively to the membrane, and being coupled by its center to the pedestal, the resonating disk being made of a metal chosen among a group comprising stainless steel, nickel-iron alloy and Molybdenum; and wherein the resonating disk comprises two opposing major surfaces, one major surface having at least one undulation creating a dissymmetry between the two major surfaces such as to generate an anisotropic resonating disk; the method further comprising: immersing the resonating element into the gas; transferring mechanical vibration from the actuating/detecting module through the membrane to the resonator via the pedestal; measuring by the actuating/detecting module a signal representative of the vibration of the resonating element; and amplifying and processing the signal representative of the vibration of the resonating element by: determining a resonance frequency; and determining the density of the gas by comparing the resonance frequency to calibration measurements.