# US 2019/0168845 A1 · Retrofit variable reluctance measurement technology tendon tension monitoring system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2019/0168845 A1 - Document ID: US20190168845A1 - Status: Published application - Kind: A1 - Application number: 16/007,897 - Filed: 2018-06-13 - Published: 2019-06-06 - Earliest claimed: 2017-12-04 - Assignees: Oil States Industries, Inc. - Applicants: Oil States Industries, Inc. - Inventors: DANIEL JOSEPH TYE; JOHN RAY BAILEYS; JOSEPH MICHAEL O'NEIL; MICHAEL EUGENE HOGAN - Web page: https://patentgrep.com/patent/US20190168845A1 ## CPC - B63B 21/502: {by means of tension legs} - E21B 43/0107: {Connecting of flow lines to offshore structures (E21B43/013 takes precedence)} - G01L 1/127: {by using inductive means (G01L1/122, G01L1/125 take precedence)} - G01L 5/101: using sensors inserted into the flexible member - G01L 5/103: using sensors fixed at one end of the flexible member - G01M 5/0025: {of elongated objects, e.g. pipes, masts, towers or railways (G01M5/0058 takes precedence)} - G01M 5/0041: {by determining deflection or stress} - G01N 27/228: {Circuits therefor (measuring capacitance per se G01R27/26)} - B63B 2021/008: {Load monitors} - 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) - E21B: EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS - G01L: MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE (weighing G01G) - G01M: TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR - 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 The invention relates to floating platform mooring and involves an improved platform mounted tendon tension monitoring system with porch mounted variable reluctance measurement technology sensors configured. The variable reluctance measurement technology sensors of this system are optimized for porch mounting. The porch mounted tendon tension monitoring system can also be configured such that the porch-mounted optimized variable reluctance measurement technology sensors are replaceable. Sensors may be replaced to extend the desired useful lifetime of a tendon tension monitoring system or in the event that a sensor happens to malfunction. A plurality of variable reluctance measurement technology sensors can be configured in sensor packs at the corners or at other locations where tendon tension monitoring can be useful for a floating platform. ## Claims ### Claim 1 A porch mounted tendon tension monitoring apparatus comprising a plurality of variable reluctance measurement technology sensors configured to be positioned between a pair of mounting flanges, wherein each of the plurality of variable reluctance measurement technology sensors are configured to measure a displacement between the pair of mounting flanges. ### Claim 2 (depends on 1) The porch mounted tendon tension monitoring apparatus of claim 1, wherein each of the plurality of variable reluctance measurement technology sensors is mounted in a mechanical strain amplifier. ### Claim 3 (depends on 1) The porch mounted tendon tension monitoring apparatus of claim 1, wherein each of the plurality of variable reluctance measurement technology sensors is mounted in a field cell between the mounting flanges. ### Claim 4 (depends on 1) The porch mounted tendon tension monitoring apparatus of claim 1, wherein each of the plurality of variable reluctance measurement technology sensors is substantially equiangularly displaced from adjacent variable reluctance measurement technology sensors. ### Claim 5 (depends on 1) The porch mounted tendon tension monitoring apparatus of claim 1, wherein each of the plurality of variable reluctance measurement technology sensors is substantially equidistant from a central axis of the mounting flanges. ### Claim 6 (depends on 1) The porch mounted tendon tension monitoring apparatus of claim 1, further comprising an outer cylindrical boot, the outer cylindrical boot surrounding the plurality of variable reluctance measurement technology sensors. ### Claim 7 (depends on 6) The porch mounted tendon tension monitoring apparatus of claim 6, wherein the outer cylindrical boot forms a void area filled with a non-conductive fluid. ### Claim 8 (depends on 1) The porch mounted tendon tension monitoring apparatus of claim 1, further comprising a computing system that is communicatively coupled to each of the plurality of variable reluctance measurement technology sensors, the plurality of variable reluctance measurement technology sensors transmitting data to the computing system. ### Claim 9 (depends on 9) The porch mounted tendon tension monitoring apparatus of claim 9, wherein the computing system is wirelessly communicatively coupled to each of the plurality of variable reluctance measurement technology sensors. ### Claim 10 (depends on 1) The porch mounted tendon tension monitoring apparatus of claim 1, further comprising one or more radial positioning devices. ### Claim 11 (depends on 1) The porch mounted tendon tension monitoring apparatus of claim 1, wherein each of the plurality of variable reluctance measurement technology sensors further comprises: one or more compression spring assemblies; and a turnbuckle assembly adapted to engage the compression spring and axially expand or contract the compression spring. ### Claim 12 A field cell employing variable reluctance measurement technology for monitoring tendon tension, the field cell comprising: two rigid endplates; an outer wall; and a displacement sensor disposed between the two rigid endplates and within the outer wall, wherein the displacement sensor measures a displacement between the two rigid endplates. ### Claim 13 (depends on 12) The field cell of claim 12, further comprising: a compression spring assembly disposed between the two rigid endplates and within the outer wall; and a turnbuckle assembly disposed outside the outer wall, the turnbuckle assembly adapted to engage the compression spring and axially expand or contract the compression spring to alter the distance between the two rigid endplates. ### Claim 14 (depends on 12) The field cell of claim 12, wherein the outer wall of the field cell is adapted to telescope and alter the distance between the two rigid endplates. ### Claim 15 A method of retrofitting a tension leg platform with variable reluctance measurement technology for tendon tension monitoring, comprising: installing one or more field cells comprising variable reluctance measurement technology sensors between a pair of mounting flanges attached to a tendon connected to a platform, each of the field cells configured to measure a displacement between the pair of mounting flanges. ### Claim 16 (depends on 15) The method of retrofitting a tension leg platform with variable reluctance measurement technology for tendon tension monitoring of claim 15, further comprising positioning the one or more field cells using a radial positioning device. ### Claim 17 (depends on 15) The method of retrofitting a tension leg platform with variable reluctance measurement technology for tendon tension monitoring of claim 15, wherein each of the one or more field cells are equidistant from a central axis of the tendon. ### Claim 18 (depends on 15) The method of retrofitting a tension leg platform with variable reluctance measurement technology for tendon tension monitoring of claim 15, further comprising removing existing field cells before installing the one or more field cells. ### Claim 19 (depends on 15) The method of retrofitting a tension leg platform with variable reluctance measurement technology for tendon tension monitoring of claim 15, wherein the one or more field cells are equiangularly displaced from each other.