Ford Car pump

[Colin Keith Williams]

My Ford Car Pump has electric wires going down directly into the
fuel.Why does this not explode on starting the car?

Can anyone explain the process for me?

--
Colin Keith Williams

[Mrcheerful]

Mr. Spigot wrote:
> "Colin Keith Williams"
> <Colin.Keith.Williams.a5c3753@autobanter.co.uk> wrote in message
> news:Colin.Keith.Williams.a5c3753@autobanter.co.uk ...
>> My Ford Car Pump has electric wires going down directly into the
>> fuel.Why does this not explode on starting the car?
>>
>> Can anyone explain the process for me?
>
> I've no explanation, but to add to your puzzlement, when I replaced
> the missus Ka fuel pump (same as on other Fords, too, by the look of
> things), there is an exposed 'rheostat' (nearest word I can think of,
> because the track is not continuous) for the fuel guage sender. I,
> too, am amazed that they even consider such an arrangement. The
> thing is certain to cause sparks with 12V across it. I can only
> assume that there isn't enough Oxygen in the tank to sustain anything
> more than the tiniest of ignitions. A bit like how you can light a
> flame at the end of a gas pipe, without it going inside. Or
> something.

petrol vapour to air ratio must be in a very narrow range for it to burn.
between 1.2 percent and 8 per cent, so you need an open tank or a leak to
have real danger of a spark from the sender unit setting it off (the sender
only uses very low power in any case) the fuel pump is sealed and a spark
inside liquid petrol would not ignite it in any case.

[Dave Plowman (News)]

In article <7LGdnRGV44cZGIvNnZ2dnUVZ8nqdnZ2d@eclipse.net.uk >,
Mr. Spigot <eff@off.com> wrote:
> I've no explanation, but to add to your puzzlement, when I replaced the
> missus Ka fuel pump (same as on other Fords, too, by the look of
> things), there is an exposed 'rheostat' (nearest word I can think of,
> because the track is not continuous) for the fuel guage sender. I,
> too, am amazed that they even consider such an arrangement. The thing
> is certain to cause sparks with 12V across it.

The current flow through it is tiny - so no spark. Rather the same as you
don't get sparks when you fit a new watch battery.

--
*Do infants enjoy infancy as much as adults enjoy adultery? *

Dave Plowman dave@davenoise.co.uk London SW
To e-mail, change noise into sound.

[Mrcheerful]

Chris Whelan wrote:
> On Mon, 30 Jul 2012 14:23:30 +0100, Mrcheerful wrote:
>
> [...]
>
>> petrol vapour to air ratio must be in a very narrow range for it to
>> burn. between 1.2 percent and 8 per cent, so you need an open tank
>> or a leak to have real danger of a spark from the sender unit
>> setting it off (the sender only uses very low power in any case)
>> the fuel pump is sealed and a spark inside liquid petrol would not
>> ignite it in any case.
>
> Would you actually get a 'spark' in the absence of oxygen?
>
> Chris

IIRC the only time a spark would not be able to travel is in a serious
vacuum, otherwise there will always be some atoms of something for it to
propagate across.

[Mrcheerful]

Chris Whelan wrote:
> On Mon, 30 Jul 2012 16:20:22 +0100, Mrcheerful wrote:
>
> [...]
>
>>> Would you actually get a 'spark' in the absence of oxygen?
>>>
>>> Chris
>>
>> IIRC the only time a spark would not be able to travel is in a
>> serious vacuum, otherwise there will always be some atoms of
>> something for it to propagate across.
>
> I was thinking of HV mains distribution switches; these are
> oil-filled in order to quench any possible arcing.
>
> Chris

I thought you were talking about in the vapour above the fuel (you mentioned
oxygen)

[Gordon H]

In message <QXxRr.306334$v24.201156@fx11.am4>, Chris Whelan
<cawhelan@prejudicentlworld.com> writes
>On Mon, 30 Jul 2012 16:20:22 +0100, Mrcheerful wrote:
>
>[...]
>
>>> Would you actually get a 'spark' in the absence of oxygen?
>>>
>>> Chris
>>
>> IIRC the only time a spark would not be able to travel is in a serious
>> vacuum, otherwise there will always be some atoms of something for it to
>> propagate across.
>
>I was thinking of HV mains distribution switches; these are oil-filled in
>order to quench any possible arcing.
>Chris
>
True. When I was a draftsman I did the drawings for an OCB (Oil
Circuit Breaker) casting. Due to inexperience I left a couple of
sharp edges on the inside of the casting, but I got the bollocking
before the pattern was made, and rounded them off.
--
Gordon H
Remove "invalid" to reply

[Duncan Wood]

On Mon, 30 Jul 2012 20:29:52 +0100, Gordon H
<Gordon_News@g3snx...............invalid> wrote:

> In message <QXxRr.306334$v24.201156@fx11.am4>, Chris Whelan
> <cawhelan@prejudicentlworld.com> writes
>> On Mon, 30 Jul 2012 16:20:22 +0100, Mrcheerful wrote:
>>
>> [...]
>>
>>>> Would you actually get a 'spark' in the absence of oxygen?
>>>>
>>>> Chris
>>>
>>> IIRC the only time a spark would not be able to travel is in a serious
>>> vacuum, otherwise there will always be some atoms of something for it
>>> to
>>> propagate across.
>>
>> I was thinking of HV mains distribution switches; these are oil-filled
>> in
>> order to quench any possible arcing.
>> Chris
>>
> True. When I was a draftsman I did the drawings for an OCB (Oil
> Circuit Breaker) casting. Due to inexperience I left a couple of
> sharp edges on the inside of the casting, but I got the bollocking
> before the pattern was made, and rounded them off.

Even they can arc, on the higher voltage ones you switch to SF6

[Gordon H]

In message <op.wia4znqrloxewg@duncan-tosh>, Duncan Wood
<nntnews@dmx512.co.uk> writes
>On Mon, 30 Jul 2012 20:29:52 +0100, Gordon H
><Gordon_News@g3snx...............invalid> wrote:
>
>> In message <QXxRr.306334$v24.201156@fx11.am4>, Chris Whelan
>><cawhelan@prejudicentlworld.com> writes
>>> On Mon, 30 Jul 2012 16:20:22 +0100, Mrcheerful wrote:
>>>
>>> [...]
>>>
>>>>> Would you actually get a 'spark' in the absence of oxygen?
>>>>>
>>>>> Chris
>>>>
>>>> IIRC the only time a spark would not be able to travel is in a serious
>>>> vacuum, otherwise there will always be some atoms of something for
>>>>to
>>>> propagate across.
>>>
>>> I was thinking of HV mains distribution switches; these are
>>>oil-filled in
>>> order to quench any possible arcing.
>>> Chris
>>>
>> True. When I was a draftsman I did the drawings for an OCB (Oil
>>Circuit Breaker) casting. Due to inexperience I left a couple
>>sharp edges on the inside of the casting, but I got the bollocking
>>before the pattern was made, and rounded them off.
>
>Even they can arc, on the higher voltage ones you switch to SF6

To be honest, I don't know what they filled the huge 132/264kV tanks in
the '50s, I was an apprentice then, and we climbed inside to wire the
heaters, so I imagine it was still oil.
--
Gordon H
Remove "invalid" to reply

[Gordon H]

In message <a7s978FiqdU3@mid................>, Huge
<Huge@nowhere.much.invalid> writes
>On 2012-07-31, Gordon H <Gordon_News@g3snx...............invalid> wrote:
>> In message <op.wia4znqrloxewg@duncan-tosh>, Duncan Wood
>><nntnews@dmx512.co.uk> writes
>
>>>Even they can arc, on the higher voltage ones you switch to SF6
>>
>> To be honest, I don't know what they filled the huge 132/264kV tanks in
>> the '50s, I was an apprentice then, and we climbed inside to wire the
>> heaters, so I imagine it was still oil.
>
>Aaargh. I guess they hadn't heard of H&S or polychlorinated biphenyls then.
>
Silly! They put the oil in afterwards!
--
Gordon H
Remove "invalid" to reply