How do pertol pump nozzles work?

In particualr, how do they know when to stop?

some sort of sensor but how full is the tank before the sensoe kicks in? I know the nozzle end isn;t immeersed in petrol nor as far as I can see, the filler tube is not full either? (soemthing to do with rate of flow?)

I've often wondered the same - the little things that keep an active mind awake at night.

I concluded it's magic

Air pressure I reckon.

When you get a strong enough pressure coming back up the nozzle it trips the switch.

Would like to know for sure though!

Straight dope

Sorry StevieB I wont tell you about santa as well, that would really ruin your day

quote:

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Originally posted by Sacal
Straight dope

Sorry StevieB I wont tell you about santa as well, that would really ruin your day

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