Fuel level senders

very rarely explode

But engine compartment fires happen regularly.

Last weekend, in my neighborhood, we had a drunken teenager hit a wall, partially ejected through the windshield (no seat belt).

The car burst into flames and the teenager was burned to death, because no one could get close enough to pull him out in time.

...Jim Thompson

--
|  James E.Thompson, P.E.                           |    mens     |
|  Analog Innovations, Inc.                         |     et      |
|  Analog/Mixed-Signal ASIC\'s and Discrete Systems  |    manus    |
|  Phoenix, Arizona            Voice:(480)460-2350  |             |
|  E-mail Address at Website     Fax:(480)460-2142  |  Brass Rat  |
|       http://www.analog-innovations.com           |    1962     |
             
I love to cook with wine.      Sometimes I even put it in the food.

It might have been. I was doing some work for Sperry/Honeywell Flight Systems at the time, and I was told that the armature hit the stator on "a" pump, due to no (fuel) lubrication.

...Jim Thompson

--
|  James E.Thompson, P.E.                           |    mens     |
|  Analog Innovations, Inc.                         |     et      |
|  Analog/Mixed-Signal ASIC\'s and Discrete Systems  |    manus    |
|  Phoenix, Arizona            Voice:(480)460-2350  |             |
|  E-mail Address at Website     Fax:(480)460-2142  |  Brass Rat  |
|       http://www.analog-innovations.com           |    1962     |
             
I love to cook with wine.      Sometimes I even put it in the food.

I got a kick out of this, at the bottom of the page:

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** HISTORICAL FOOTNOTE: Aluminum was originally named "alumium" by Sir Humphry Davy, who later changed it to "aluminum" (perhaps in an attempt to make it more Latinized since alumen is Latin for alum, the aluminum compound that the name is derived from). The British (and allied English speakers) shortly thereafter changed the name once more, this time to "aluminium" so that it would again match the pattern of most other elements (helium, sodium, etc.), while the North Americans eventually decided to keep the second, slightly more traditional name. I predict that North Americans will adopt the more regular "-ium" spelling by the year 2050, prompting the British to start calling it "alumininium". At that point debate can begin on changing "platinum" to "platinium"

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Cheers! Rich

On Thu, 19 May 2005 16:13:00 +0800, "Rheilly Phoull" put finger to keyboard and composed:

I've never really doubted that petrol tanks are safe. I just wanted to know why. As for low current being the reason, I'd expect that the tank would need to tolerate the situation where the full supply voltage was applied to the sender when it was at the low end of its resistance range. I imagine this could occur as the result of a wiring error during a dashboard repair, say, or if the fuel gauge failed in some peculiar way.

- Franc Zabkar

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On 19 May 2005 02:08:52 -0700, snipped-for-privacy@ieee.org put finger to keyboard and composed:

Thanks, that makes sense. I guess it is very difficult to achieve a stoichiometric ratio inside the fuel tank.

I recall a friend who was a panel beater telling me that he used to weld petrol tanks after filling them with fuel. His colleagues thought he was mad, but he survived, only to die of prostate cancer many years later.

- Franc Zabkar

--
Please remove one \'s\' from my address when replying by email.

The shaft of the rheostat came out of the case via a bearing and it had a small cage fitted with what I suspect was a carbon graphite seal. the float arm was of sufficient length that the inertia required to rotate the shaft was of little consequence.

My brother was experienced at welding fuel tanks. He connected the exhaust pipe from a running vehicle to the tank so that it became filled with carbon monoxide and could safely be brazed with an oxy acetylene torch. He also demonstrated the non-flammability of petrol (in open air mind you) by flicking a lighted cigarette butt directly into a container of petrol. ffft... out went the glowing butt.

It appears that fuel in a properly capped fuel tank is almost impossible to ignite according to

QUOTE: The fuel tank of a car or light goods vehicle can contain a large quantity of petrol and petrol vapours. Extensive firefighting experience and lab tests have shown that fuel tanks very rarely explode during a vehicle fire. Though these reservoirs of potentially dangerous and explosive liquid and its vapours may appear to present a real risk, it is however nearly impossible to ignite the contents in a fuel tank that is properly capped. This is because the vapours of petrol are much heavier than air and tend to fill the tank completely to the top. The vapour pressure of petrol is such that it tends to form a mixture with air in the tank that is above the explosive limit and can not be ignited. ENDQUOTE:

Full document here

Even with the potential for this particular sender to generate arcing the possibility of an explosion is considered to be impossible.

mix

Those fuel pumps actually use the fuel to help cool them ! The commutator area is sealed however !

Actually the problem lies not so much with the FQIS itself but wiring ageing problems in old jets.

I've seen pics of arc-over between cables in airframes and it's no joke. The presumption is that something arced over to the FQIS and that provided sufficient ignition energy.

I doubt that the full truth will ever some out.

Having said that - the NTSB's conclusion is likely correct. There have been several aircraft lost on the ground due to fuel tank explosions too.

Graham

Don't you mean the scavenge pump ( that was never recovered IIRC ) ?

Graham

very rarely explode

Yep, caused by the battery being compromised. All that acid spilling on all that metal, plus the electochemical energy stored in there getting out due to shorts, etc.

Charlie

very rarely explode

Except in Hollywood !

Graham

Could explain a few subsequent flying saucer sightings .

--
Terry Pinnell
Hobbyist, West Sussex, UK

It's not uncommon to feed a pipe from the exhaust of a running car into a fuel tank so you can weld it safely. It's easier to remove the oxygen than to remove the residual fuel...

very rarely explode

In frontal crashes.

Yep. All of his buddies are whining and moaning now, but they didn't think enough of him to stop him from leaving the party in a totally inebriated state :-(

The cops are saying his estimated impact velocity was 70MPH. This was in the heavily curved area of Ray Road in Ahwatukee Foothills (for those of you who know the area).

...Jim Thompson

--
|  James E.Thompson, P.E.                           |    mens     |
|  Analog Innovations, Inc.                         |     et      |
|  Analog/Mixed-Signal ASIC\'s and Discrete Systems  |    manus    |
|  Phoenix, Arizona            Voice:(480)460-2350  |             |
|  E-mail Address at Website     Fax:(480)460-2142  |  Brass Rat  |
|       http://www.analog-innovations.com           |    1962     |
             
I love to cook with wine.      Sometimes I even put it in the food.

very rarely explode

Darwin Strikes Again! >:->

Cheers! Rich

--
Cheers!
Rich
 ------
"Objectivity is to a newspaper what virtue is to a woman. -- Joseph Pulitzer"

I always thought those fluids had high flash points. Then I sprung a pinhole leak in a power steering hose and had a fire going on the exhaust manifold that rivaled a furnace burner ;-)

...Jim Thompson

--
|  James E.Thompson, P.E.                           |    mens     |
|  Analog Innovations, Inc.                         |     et      |
|  Analog/Mixed-Signal ASIC\'s and Discrete Systems  |    manus    |
|  Phoenix, Arizona            Voice:(480)460-2350  |             |
|  E-mail Address at Website     Fax:(480)460-2142  |  Brass Rat  |
|       http://www.analog-innovations.com           |    1962     |
             
I love to cook with wine.      Sometimes I even put it in the food.

very rarely explode

In Hollywood vehicles sometimes explode in mid air after going off a cliff. :-)

On Fri, 20 May 2005 14:55:09 GMT, Rich Grise put finger to keyboard and composed:

Genuine tin foil hats are made from stannum. In any case, plumbum would be better for keeping out the harmful radiation. Argentum and aurum may not work as well, but the sort of people who would wear them wouldn't be seen dead in aluminium apparel.

- Franc Zabkar

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