Science & Environment

Wireless device sends power through armoured doors

Demonstration of a wireless device that could be used to transmit power and communications signals through armoured doors (Image: BAE Systems)
Image caption The device can transmit power wirelessly through several inches of steel

Scientists in the UK have developed technology that allows power to be transmitted wirelessly through several inches of steel.

The developers, at BAE Systems, say the device could be used to send power and communications signals through submarine hulls or armoured doors.

The device uses very high frequency acoustics - essentially converting the signal into sound waves.

The company has started environmental tests on the technology.

These should ensure, it says, that it will be able to survive the 25-year lifespan and extreme conditions required on the outer hull of a submarine.

Currently the system is still at demonstration stage, but the developers claim that it could eventually help save millions of pounds currently spent adapting submarine hulls for the necessary communications equipment.

Dr John Bagshaw, a technology executive from BAE Systems Advanced Technology Centre in Bristol, explained that, currently, 300 holes have to be drilled in a submarine hull to accommodate the sensors and communications technology it requires.

"In each of these holes, they fit special valves called penetrators," he explained. And each of those costs from £20,000 to £750,000 pounds.

"It then costs up to £50,000 to weld the valves in to the holes, and through their life they have to be checked to ensure that the welds aren't cracking."

"So through the 25-year life of a submarine, the total cost of all of its penetrators is in order of £80 million."

Dr Bagshaw said that, as well as military applications, the technology could potentially be useful in the nuclear and oil industry.

"If you want sensors on the inside of a reactor vessel, you obviously don't want to be drilling holes in that vessel," he said.

Image caption The device transmits power as high frequency sound waves

BAE is currently undertaking environmental testing to take the technology from demonstration-stage to being used on a submarine. This is likely to take several years.

"This is emerging technology and we have to make sure the engineering is perfect," said Dr Bagshaw.

But he is optimistic about its potential. In the earliest demonstrations to submarine commanders, he sent power to a DVD player through a block of steel and played the film Das Boot.

"We got a top quality image, and the response from the Navy was: 'this is brilliant - we want to get it onto a boat'."

One key aspect that the developers are yet to perfect is the adhesive that will be used to stick the connectors to the outside of a submarine or vehicle.

But this is not entirely unchartered territory. Scientists at Woods Hole Oceanographic Institution are using lower frequency acoustics to transmit data from temperature sensors on the outside of their research vessels.

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