Electricity Over Glass

guddan writes "Running a live wire into a passenger jet's fuel tank seems like a bad idea on the face of it. Still, sensors that monitor the fuel tank have to run on electricity, so aircraft makers previously had little choice. But what if power could be delivered over optical fiber instead of copper wire, without fear of short circuits and sparks? In late May, the big laser and optics company JDS Uniphase Corp., in San Jose, Calif., bought a small Silicon Valley firm with the technology to do just that."

Comments

Intrinsic Safety.

[GrpA]

There is nothing wrong with running wires into petrol tanks for sensors... Take a good look at how badly made the rheostats in everyone's pertol tanks are made. Most engineers freak out when they see them for the first time.

However the design is what is known as "Intrinsically Safe"... ie, it can't cause an explosion.

Currents, voltages are limited. Components are overrated by a set amount.

I've never heard of any intrinsically safe circuit igniting gasoline.

So what if you use fiber optics to provide the power. It's still electronic circuits in the tank, except now they are a whole lot more complicated and have power generation and regulation circuits, which make it a whole lot more dangerous...

And please don't just say encapsulate the dangerous stuff, because I'm sure that won't explode with a pressure build up if a component dies (as they tend to do in regulated power circuits).

It really scares me how such "great" ideas like this seem sane, when the original technology was probably safer.

GrpA

Formidably silly article

[Ancient_Hacker]

Formidably silly article, for many reasons:

• Exploding gas tanks are very low on the list of problems, sorted by frequency and severity. If we spend money on these less severe problems, we're taking money away from figting more serious and cost-effectively attakcable problems.
• The problem is having explosive mixtures in gas tanks. Rather easily solved by plumbing a little engine exhaust gas into the tanks to displace the oxygen. Done for decades on tanker ships.
• The typical sensors in airplane tanks are capacitive dielectric guages. These can easily be made to run on microwatts of signal, not enough to cause ignition.
• Even if the sensors were a problem, which they're not, and you replaced them all with some new method, you'd still have all the other sources of ignition, including sulfur chemical catalsys, static discharges, lightning, friction, and more. You need to make the stuff non-explosive or ignitable, see point #1.