Explosion proof optical lenses & windows

During this project, the team composed of Teknova researchers and Hernis engineers have defined the optical prescription required on the protective lenses. The team moved then to identify a manufacturing process that could be cost effective and reproductive.

Explosion proof optical lenses and windows are important components for all the advanced camera-based surveillance systems for marine and oil&gas operations. The surveillance solutions, in this case developed by Hernis contribute to increase efficiency and provide safety for people and equipment in hazardous areas and under extreme conditions.

For a camera system to be permanently fixed on an O&G platform it has to be Ex. approved.  Explosion proof CCTV cameras require transparent windows or lenses that can resist to the tests described in the standard NEK EN 60079-0:2009, or in other word resist to: 46,5 bar pressure, temperature from +80 to -65° C and impact of 40 joules.

No standard lenses can endure such treatment, as a result, the active optical lenses of the camera are usually placed behind a protective glass, 12 mm thick, and thermally strengthened soda lime glass. The use of such window is detrimental to the CCTV product as it affects the (i) image color and (ii) increases the optical aberrations.

As the cameras becomes smarter and smarter, (e.g. smart cameras understand and analyses the observed scene) it is important that the optical system does not limit the technology progresses. To this end high optical quality explosion proof lenses and windows are important for the development of machine vision in harsh environment.

During this project, the team composed of Teknova researchers and Hernis engineers have defined the optical prescription required on the protective lenses. The team moved then to identify a manufacturing process that could be cost effective and reproductive. To this end more than 150 samples where manufactured out of different type of crown glass and polycarbonates. Each windows where individually optically and Ex. proof tested. Out of the samples tested, one specific material passed the costs, optical and engineering specifications. Hernis is now in the process of deploying this knew knowledge in their products.

R&D projects as described above are imperative to sustain the operation in a high cost country like Norway. Experience shows that one has to be a world technology leader to survive in the long-term perspective.