Overcome the last frontier in fibre optic sensing for ultra-harsh environments

New nickel (Ni), automated, continuous coating system for FBG and Distributed Fibre Optic Sensors (FOS) operating in ultra-harsh environments

Context

The benefits of fibre optic sensors (FOS) for ambient conditions over their conventional counterparts (thermocouples, gauges, or extensometers) are well established; they are smaller, lighter, longer lasting and can provide an enormous number of measurement points at a fraction of total sensor weight.

The last frontier in fibre optic sensing is now ultra-harsh environments (corrosion, oily, temperatures
> 350ºC) as:

• Conventional polymeric coated FOS are not resistant to hydrogen penetration, and/or
• Adhesives used to attach the FOS to the structures are not durable.

Commercially available metallic coated optical fibres for industrial operation are not sufficiently performing either in ultra-harsh environments:

• Either maximum temperature for long-term operation is restricted to 450ºC, or coating is very costly
• Coating thickness is also restricted to around 25µm for a typical single mode optical fibre, which limits its application in an industrial environment (too fragile)
• Alternatively, optical fibres may be packaged in metallic capillary tubes to be safely installed. However, packaging makes it impossible for the fibre to be sensitive to strain variations (or indirectly to load, fatigue, cracks detection, pressure, etc.), and only temperature variations are measurable with FOS

Applications

The process has been designed to enable condition-based maintenance and energy efficiency in ultra-harsh environments. Two scenarios have been particularly considered:

• Continuous, distributed temperature monitoring of a high number of sensor points (<50)
• Simultaneous strain AND temperature monitoring

Use cases

Several use cases have already been identified:

Energy generation Operations management in thermal, geothermal, biofuel, solar plants or nuclear plants.

Aircraft, aerospace, naval or railway Temperature & strain monitoring in combustion systems or structures with difficult access

Metallurgy Monitoring of casting process, moulds, components, etc.

General industry Monitoring of hardly accessible machinery, components, and structures (i.e., heat exchangers).

Technology Readiness Level & Time to Market

TRL 7 – System prototype demonstration in operational environment

Thermal fatigue and stress tests have been performed in lab environment on sensors embedded in anti-friction material.

 Preliminary prototypes were validated in:

• Continuous, distributed temperature monitoring of a high number of sensor points (<50)
• An energy storage module of a solar thermal plant
• In a test bed embedded in a ship's bearing, simulating the normal operation of this component

Sensors were finally validated under real conditions in:

• A combined cycle power superheater
• A biomass plant superheater

IP Status

Patent pending. Patent will cover the fibre coating process and the implementing equipment, with particular focus on the monitoring and quality control processes for homogeneous custom encapsulation.

Business Opportunities

• IP licensing
• Contract manufacturing services for small orders

Contact in KIM

Carlos Alvarez – Marketing Manager
calvarez@kimbcn.org
+34 93 266 71 38