LVDT assembly enhances extensometer reliability
A
Macro Sensors product story
Edited by the Engineeringtalk editorial team
Jan 14, 2009
Macro Sensors has designed a pressure-balanced, oil-filled and double-bellows-sealed LVDT assembly to enhance the reliability of multiple redundant LVDT-based extensometers.
The extensometers are mounted longitudinally around the circumference of the structural member to monitor structural integrity.
The LVDTs enabled measurement of the extension of the structural members to a fraction of a microstrain.
For the huge loads on oil platforms, total movement being measured is typically less than 2mm.
Because required measurement must be obtained in seawater depths down to 7,500ft, with external pressure of approximately 3800psi and where service life requirements are a minimum of 20 years, Macro Sensors designed its LVDT assembly from 316 SS and Inconel 625 for pressure and corrosion resistance.
These materials enhance the high reliability required of this instrument so that it will continue to operate for at least 10 years, even if the device is fully exposed to seawater.
The LVDTs from Macro Sensors also resolved the problem of getting a useful signal back to the surface, even in great water depths, for monitoring, recording, and controlling thrusters and ballast transfer pumps.
The extensometer housing can be outfitted with a variety of mechanical terminations to facilitate connection to the structural members.
To minimise the number of pressure-sealed connections, a 4-20ma loop-powered I/O was utilised, which the customer converted to a RS485 digital signal for transmission to the surface.
The two-wire I/O also minimised any noise going to the digital converter that was contained in a high-pressure sealed bottle located nearby.
An advantage of choosing an LVDT for this task is its repeatability, regardless of offsets due to pressure and/or temperature.
Offsets can be easily corrected in the data acquisition system on the platform above.
The LVDT extensometers performed favourably compared to results obtained from lower reliability alternative technologies, such as resistance strain gauges bonded to the same structural members.
Not what you're looking for? Search the site.
Google Ads
Contact Macro Sensors
Related Stories
- Zytek uses Renco R35i encoders to develop gearbox
- Airbus uses Balluff sensors in A380 restrooms
- Thermal imaging camera to scan homes
- Linear position sensors used in ATM bill detector
- OMS fits Scancontrol into internal weld inspector
Articles by product category
- Consultancy and Services (903)
- Machine Building (4,517)
-
Engineering Design Software (6,179)
- Engineering Design Software (12)
- 2D CAD software (200)
- 3D CAD software (1,157)
- FEA and structural analysis software (369)
- Fluid, thermal, noise, vibration software (334)
- Simulation, modelling, validation software (914)
- Rendering, visualisation, styling software (196)
- Materials design and moulding design software (151)
- Process, instrumentation, automation software (258)
- Electrical design software (164)
- Publishing and documentation software (229)
- Maths, charting, statistics, QA software (317)
- Data, document management software (310)
- CAM, CNC, production management software (568)
- File conversion software, data capture (351)
- PLM and collaboration software (649)
-
Drives, Motors and Controls (3,361)
- Drives, Motors and Controls (1)
- Precision Motors and Gears (411)
- Industrial Drives/Controls (1,276)
- Linear Drives and Motors (114)
- Industrial Motors (497)
- Stepper and Servo Drives, Motors, Controls (1,060)
- Small Mechanical Components, Joining, Tools (1,975)
-
Control and Instrumentation (5,028)
- Plantwide control (1,324)
- Plant- and Machine-Wide Communications (1,174)
- Smaller-Sized PLCs (387)
- CNC and Motion Controllers (184)
- Mid-range and Large PLCs (201)
- Power Supplies, Uninterruptible Power (562)
- HMIs/Operator Interfaces (294)
- Logic Controllers, Timers and Relays (96)
- Cabling, Conduit, Signal Conditioning (806)
-
Monitoring, Measurement and Quality (5,459)
- Monitoring, Measurement and Quality (1)
- Data acquisition Software and Communications (494)
- Data Acquisition Hardware and PC I/O Boards (472)
- Electrical and Electronic Testing, PAT Equipment (630)
- Form/co-ordinate, optical, vision instruments (703)
- Gauges, Indicators and Instruments (440)
- Data loggers (422)
- Materials testing equipment (421)
- Telecomms/network test equipment, software etc (154)
- Testing and Calibration Services and Information (500)
- Testing, analysing and monitoring equipment (1,222)
-
Electrical and Electronic Equipment Design (4,160)
- Batteries, chargers and circuit protection (555)
- Connectors, Terminals, Busbars, Slip Rings (679)
- Enclosures and Equipment Cooling Fans (709)
- Knobs, Handles and Enclosure Hardware (420)
- PCs and Embedded Systems (798)
- Electrical and Electronic Subassemblies (369)
- Electrical and Electronic Components (630)
-
Materials and Processing (2,963)
- Materials and Processing (5)
- Materials and components (2,215)
- Rapid Prototyping (458)
- Materials processing and testing (285)
-
Engineering Industry News, Resources (6,093)
- Engineering Industry News, Resources (4)
- Engineering Business News, Views (388)
- Engineering Exhibitions, Events (562)
- Engineering Conferences (425)
- Engineering Seminars (400)
- Engineering Industry Developments, Awards (633)
- Engineering Guides, Newsletters (349)
- Engineering Recruitment, Employment (219)
- Engineering Training Courses (433)
- Engineering Education, Resources, Standards (838)
- Engineering Industry Reports, Surveys (597)
- Electronic Resources for Engineers (278)
- Health and Safety Legislation (402)
- Health and Safety Strategy, Risk Assessment (113)
- Health and Safety Consultancy, Software (175)
- Health and Safety Events, Training, News (277)
-
Powertrain Design (3,598)
- Powertrain Design (2)
- Bearings (939)
- Chains and belts (326)
- Gears, brakes, couplings and engines (1,441)
- Hydraulic Components (471)
- Lubricants (418)
-
Capital Equipment (3,387)
- Capital Equipment (1)
- Manufacturing Machinery and Plant Equipment (468)
- Production line blowers and fans (62)
- Compressors and Air Treatment (510)
- Electronics Manufacturing, Tools, Instruments (192)
- Electrical hardware (131)
- Machinery and Production Equipment (1,093)
- Robotics, Handling and Storage (930)
-
Sensors (7,080)
- Sensors (8)
- Accelerometers and Vibration Sensors (427)
- Loadcells, Force Sensors, Torque Sensors (699)
- Pressure sensors (621)
- Flowmeters and Flow Sensors (618)
- Level Sensors and Leak Detectors (527)
- Linear Position Sensors (399)
- Rotary Position, Tilt and Angular Sensors (546)
- Proximity Sensors (700)
- Gas, Chemical, Radiation, Magnetic Sensors (284)
- Humidity and Environmental Sensors (152)
- Temperature sensors (612)
- Vision and Colour Sensors (1,384)
- Barcode Sensors (103)
- Valves, Pumps, Process Hardware (3,623)
