The benefits of fiber 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 fiber 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
New nickel (Ni), automated, continuous coating system for FBG and Distributed Fiber Optic Sensors (FOS) operating in (positive T) ultra-harsh environments. The system comprises:
- Coating method automated electroplating process for different metallic coatings
- Coating equipment design specifications
- Speed: 0.1-10mm/s
- Thickness: 0.2-1.2mm
- Software for signal analysis
Our new nickel (Ni) coating system is:
- Versatile: The process can be applied to either FBG or distributed fiber optic sensors (Brillouin, Rayleigh…)
- Automated and scalable: The process enables continuous manufacturing of coated fiber optic sensors.
- Customizable: The system can adapt to different thicknesses in order to be applied directly in harsh environments and be able to monitor both temperature and strain (or pressure, fatigue, load, etc.). Total diameter (single mode optical fibre plus coating) may range between 150µm and 1.2mm
Also, the resulting Ni coated optical fibre can be embedded in metals by welding, laser, ultrasound or other bond processes to generate smart/nervous/intelligent structures, components or materials.
Sensors coated using this system will be:
- Stable, resistant and durable in ultra-harsh environments (corrosive, temperatures >350ºC and other aggressive environments): The coating allows it to withstand working temperatures of up to 850ºC and peaks of up to 1000ºC.
- Manipulable Coated fibres do not easily deteriorate/break.
- Efficient The sensors can monitor strain and temperature simultaneously.
- Highly accuratemeasurement of strain (± 1µƐ) or temperature (± 0.1ºC) without loss of resolution, compared to conventional metal coverings.
- Cost-effective nickel is >50% cheaper than other metals used in FOS coating for ultra-harsh environments.
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
Patent pending. Patent will cover the fiber coating process and the implementing equipment, with particular focus on the monitoring and quality control processes for homogeneous custom encapsulation.
- IP licensing
- Contract manufacturing services for small orders
- Fiber Optics
- Strain Sensor
- Temperature Sensor
- Fiber Bragg Gratting
- Distibuted FOS