# US 9,518,894 B2 · Device for measuring vibration amplitudes of the blade tips in a turbomachine > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,518,894 B2 - Document ID: US9518894B2 - Status: Granted - Kind: B2 - Application number: 13/888,715 - Filed: 2013-05-07 - Published: 2014-12-04 - Granted: 2016-12-13 - Earliest claimed: 2012-05-15 - Assignees: Snecma - Applicants: Snecma - Inventors: Andre Leroux; Serge Del Arco; Olivier Follerot; Michel Herbault; Philippe Armand Hugbart; Fabien Pouchard; Etienne Tulie - Web page: https://patentgrep.com/patent/US9518894B2 ## CPC - G01M 15/14: Testing gas-turbine engines or jet-propulsion engines - F01D 21/003: {Arrangements for testing or measuring (for measuring vibrations G01H)} - G01B 11/14: for measuring distance or clearance between spaced objects or spaced apertures (G01B11/26 takes precedence; rangefinders G01C3/00) - G01H 1/006: {of the rotor of turbo machines} - G01H 9/006: {the vibrations causing a variation in the relative position of the end of a fibre and another element} - G01M 7/00: Vibration-testing of structures; Shock-testing of structures (G01M9/00 takes precedence) - G01N 21/1702: {with opto-acoustic detection, e.g. for gases or analysing solids} - G01N 2021/1706: {in solids} - G01N 2201/08: Optical fibres; light guides - G01M: TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR - F01D: NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES (machines or engines for liquids F03; non-positive displacement pumps F04D) - G01B: MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS - G01H: MEASUREMENT OF MECHANICAL VIBRATIONS OR ULTRASONIC, SONIC OR INFRASONIC WAVES - 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) ## Abstract A device for measuring vibration amplitudes of the blade tips in a turbomachine is provided. The device includes a support mounted in an orifice of a casing of a turbomachine, in which are housed two optical guides for the emission and reception of a light signal exiting inside the casing across from the tips of the blades of a turbine wheel Each optical guide includes an optical fiber connected by a mechanical connector to a needle of which the core is made of a material able to transmit a light signal and which is resistant to temperatures less than or equal to 1100° C. and which exits at its distal end in the casing across from the blade tips. ## Claims ### Claim 1 A device for measuring vibration amplitudes of the blade tips in a turbomachine, comprising: a support mounted in an orifice of a casing of a turbomachine and wherein are housed first and second optical guides exiting the casing across from the tips of the blades of a turbine wheel, with the first optical guide being connected to a source of light for the propagation of a light signal to the blade tips and the second optical guide being connected to means for processing and analysing the light signal reflected by the blade tips, wherein each optical guide comprises an optical fiber connected at one end by a mechanical connector to a rigid needle of which a core is made of a material able to transmit a light signal and which is resistant to temperatures equal to 1100° C. and which exits at a distal end thereof inside the casing across from the blade tips. ### Claim 2 (depends on 1) The device according to claim 1, wherein the support is mounted in an orifice of a boss of the casing and comprises a flange formed on an external surface thereof, on which external surface is mounted radially abutting from an exterior a member for blocking the support on the boss, with the member for blocking being fixed in a detachable manner to the boss. ### Claim 3 (depends on 2) The device according to claim 2, wherein the member for blocking is formed by a nut mounted around the support and screwed onto a threaded internal surface of the orifice of the boss. ### Claim 4 (depends on 1) The device according to claim 1, wherein each connector comprises an axially split tube wherein are maintained in contact the proximal end of the needle and the distal end of the optical fiber. ### Claim 5 (depends on 1) The device according to claim 1, wherein the support comprises two tubular housings converging towards an interior of the turbomachine on the blade tips and exiting inside the casing and wherein are inserted from an exterior the needles of the optical guides. ### Claim 6 (depends on 5) The device according to claim 5, wherein each optical guide comprises a bushing mounted around a proximal end portion of the needle, with the bushing comprising an external annular edge coming to abut radially towards an interior on an internal radial shoulder of the housing of the support wherein is mounted the needle of the optical guide. ### Claim 7 (depends on 5) The device according to claim 5, wherein each needle is retained radially towards an exterior in the housing by a cylindrical part mounted around the distal end portion of the optical fiber and in axial abutment in a direction of the needle on an external annular edge of said distal end portion, the cylindrical part comprising a threading on an external surface thereof for screwing into a corresponding threading of an internal surface of the housing. ### Claim 8 (depends on 7) The device according to claim 7, wherein the annular edge of the distal end portion of each optical fiber is formed with an added part crimped around said distal end portion. ### Claim 9 (depends on 1) The device according to claim 1, wherein the core of the needle is surrounded by a metal sheath. ### Claim 10 (depends on 9) The device according to claim 9, wherein a distal surface of the core of the needle is offset radially towards an interior in relation to a distal end of the sheath. ### Claim 11 (depends on 9) The device according to claim 9, wherein the core of the needle is surrounded by a titanium sheath. ### Claim 12 (depends on 1) The device according to claim 1, wherein the core is made of sapphire. ### Claim 13 (depends on 1) A turbomachine comprising the device according to claim 1. ### Claim 14 (depends on 1) A system for measuring vibration amplitudes of the blade tips in a turbomachine, comprising the device according to claim 1, with the first optical guide being connected at a proximal end thereof to a laser source and the second optical guide being connected at the distal end thereof to means for amplifying, sampling, converting and transferring data to the means for processing. ### Claim 15 A device for measuring vibration amplitudes of the blade tips in a turbomachine, comprising: a support mounted in an orifice of a casing of a turbomachine and wherein are housed first and second optical guides exiting inside the casing across from the tips of the blades of a turbine wheel, with the first optical guide being connected to a source of light for the propagation of a light signal to the blade tips and the second optical guide being connected to means for processing and analysing the light signal reflected by the blade tips, wherein each optical guide comprises an optical fiber connected by a mechanical connector to a rigid needle of which a core is made of a material able to transmit a light signal and which is resistant to temperatures equal to 1100° C. and which exits at a distal end thereof inside the casing across from the blade tips, and wherein each connector comprises an axially split tube wherein are maintained in contact the proximal end of the needle and the distal end of the optical fiber.