# US 8,770,125 B2 · Floating support or vessel equipped with a device for detecting the movement of the free surface of a body of liquid > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,770,125 B2 - Document ID: US8770125B2 - Status: Granted - Kind: B2 - Application number: 13/320,487 - Filed: 2010-05-07 - Published: 2012-04-26 - Granted: 2014-07-08 - Earliest claimed: 2009-05-14 - Assignees: Saipem S.P.A. - Applicants: Alain Guerrier - Inventors: Alain Guerrier - Web page: https://patentgrep.com/patent/US8770125B2 ## CPC - B63B 39/005: {Equipment to decrease ship's vibrations produced externally to the ship, e.g. wave-induced vibrations (propulsion mountings for anti-vibration purposes B63H21/30; vibration dampers, suppression of vibration in systems F16F)} - F17C 2260/016: Preventing slosh - F17C 2270/0105: Ships - B63B: SHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING (arrangements of vessel ventilation, heating, cooling, or air-conditioning B63J2/00; floating substructures as supports of dredgers or soil-shifting machines E02F9/06) - F17C: VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES (storing fluids in natural or artificial cavities or chambers in the earth B65G5/00; construction or assembling of bulk storage containers employing civil-engineering techniques E04H7/00; variable-capacity gas-holders F17B; liquefaction or refrigeration machines, plants, or systems F25) ## Abstract A ship or floating support for transporting/storing liquid constituted by a liquefied having a plurality of beacon devices for detecting roughness of liquid within the tank, each beacon having a vibration sensor for measuring amplitude of the acceleration (g) as a function of time (t) of the vibratory movements of a wall on which the beacons are fastened, and an electronic calculation unit having a microprocessor and memory for processing a signal as measured by the vibration sensor, and a device for transmitting the signal to a supervisor or central unit. ## Claims ### Claim 1 A ship or floating support for transporting or storing a liquid constituted by a liquefied gas, cooled in at least one tank having a width, said tank being thermally insulated and having at least said width greater than 20 m, and a volume greater than 10,000 m3, said tank being supported inside a hull of a ship by a carrier structure, the ship having a plurality of beacons for detecting roughness of the liquid within said tank(s), each of said beacons comprising: a) a vibratory accelerometer vibration sensor for measuring the amplitude of acceleration (g) as a function of time (t) of vibratory movements of a wall of said tank or of a wall of the ship that is not in contact with sea water, said wall of the ship including a deck of the ship or a wall of an internal structure of the ship, said vibration sensor being fastened on said wall outside said tank; b) an electronic calculation unit having a microprocessor and an incorporated memory, for processing a signal as measured by said vibration sensor, to yield a processed signal, in order at least to eliminate background noise from said measured signal that is specific to the ship, and to detect movement of the liquid inside said tank by comparing values of the processed signal with predetermined threshold values beyond which the roughness of a liquid free surface is considered as constituting a risk of damaging deformation or deterioration of said wall; and c) a transmitter for transmitting said processed signal of the electronic calculation unit to a central unit. ### Claim 2 (depends on 1) The ship or floating support according to claim 1, wherein said vibration sensor is a piezo-resistive accelerometer. ### Claim 3 (depends on 1) The ship or floating support according to claim 1, wherein said transmitter comprises an antenna and a transceiver suitable for transforming said processed signal into radio waves. ### Claim 4 (depends on 1) The ship or floating support according to claim 1, wherein said transmitter comprises optical fiber cables and a signal processing interface for transforming said processed signal into light signals suitable for being conveyed via said optical fiber cables. ### Claim 5 (depends on 1) The ship or floating support according to claim 1, wherein said vibration sensor is constituted by a three-axis vibratory accelerometer. ### Claim 6 (depends on 1) The ship or floating support according to claim 1, wherein one of said beacons further includes an additional device suitable for detecting movements specific to the ship and for triggering activation by said beacons of all said electronic calculation units, said triggering of activation of said electronic calculation units taking place from a predetermined threshold value of an amplitude of said movements of the ship. ### Claim 7 (depends on 6) The ship or floating support according to claim 6, wherein said additional device suitable for detecting movements of the ship is a pendular inclinometer or an inertial unit-suitable for determining a roll angle of a side wall of a hull of the ship or floating support, said threshold value being a roll angle of at least 5° relative to vertical. ### Claim 8 (depends on 1) The ship or floating support according to claim 1, wherein said electronic calculation unit is suitable for being activated from a measurement of a threshold value for said amplitude of acceleration (g) as a function of time (t) of said vibratory movements. ### Claim 9 (depends on 1) The ship or floating support according to claim 1, wherein each said beacons is powered by a power supply consisting of a storage battery or a supercapacitor powering said vibratory accelerometer, and said electronic calculation unit. ### Claim 10 (depends on 9) The ship or floating support according to claim 9, wherein said power supply further includes a thermocouple in which a cold junction is installed between a cold internal wall of said tank and said beacon, said beacon constituting a hot junction of the thermocouple, said thermocouple serving to generate a current continuously for powering said beacon and continuously recharging said storage battery or supercapacitor. ### Claim 11 (depends on 1) The ship or floating support according to claim 1, wherein said beacons are secured to a deck of the ship and/or to a side wall of a system for supporting and insulating walls of said tank inside a hull of the ship facing a side wall of the hull, said beacons being situated in the corners of said tank at longitudinal ends of said tank. ### Claim 12 (depends on 11) The ship or floating support according to claim 11, wherein said beacons are positioned facing a dihedral angle formed by corners of said tank between a vertical longitudinal side wall, a vertical transverse wall, and a ceiling wall of said tank, or a trihedron formed by two planes of a ceiling wall of said tank that are disposed angularly relative to each other, and a transverse vertical side wall of said tank. ### Claim 13 (depends on 1) The ship or floating support according to claim 1, comprising a methane tanker transport ship converted into a floating storage ship that is anchored at a fixed location, in which a filling level of at least one tank is determined as a function of roughness of the liquid contained in said tank as detected and calculated by said beacons. ### Claim 14 (depends on 6) A method of detecting roughness of a liquid free surface within one or more tanks of a ship according to claim 6, the method comprises the following successive steps: 1) providing said measured amplitude of acceleration (g) as a function of time (t) of said vibratory movements of said wall with said vibration sensor; 2) triggering said activation of said electronic calculation unit when said the movement of the ship reaches a said predetermined threshold value; 3) performing said signal processing with said electronic calculation unit to yield said processed signal; and 2) transmitting values of said processed signal obtained in step 3) from said electronic calculation unit to said central unit. ### Claim 15 (depends on 1) The ship or floating support according to claim 1, wherein said liquefied gas is selected from methane, ethylene, propane and butane. ### Claim 16 (depends on 1) The ship or floating support according to claim 1, wherein said tank is a cylindrical tank having a polygonal cross section. ### Claim 17 (depends on 14) The method of claim 14, wherein in step 3) said electronic calculation unit performs the following signal-processing steps: 3.1) using a Fourier transform in real time to process a variation of said measured signal to calculate a variation in amplitude of acceleration (g) as a function of frequency (F) of a vibratory wave of said measured signal over a given period of time (Δt), and then calculating an energy spectral density and/or a power spectral density; 3.2) filtering the variation signal obtained in step 3.1) to eliminate therefrom the background noise due to vibration that is specific to the ship; then 3.3) calculating maximum time acceleration values obtained by an inverse Fourier transform of said variation in amplitude of acceleration (g) as a function of frequency (F) obtained in step 3.2), and calculating values of maximum energy spectral density (e1, e2) and/or of maximum power spectral density (P0), respectively, of said energy spectral density and/or said power spectral density calculated in step 3.2); and 3.4) comparing said maximum time acceleration values and said maximum energy spectral density values (e1, e2) and/or said maximum power spectral density values (P0) respectively of step 3.3) with respective predetermined threshold values (S1, emax, pmax) thereof from which roughness of said liquid free surface is considered as constituting a risk of damaging deformation or deterioration to said wall; wherein in step 4), said electronic calculation unit transmits said maximum time acceleration values, said maximum energy spectral density values (e1, e2), and/or maximum power spectral density values (P0), respectively, of step 3.3) to the central unit if said threshold value of step 3.4) is reached by at least one of said beacons.