The Sparking Tankers

Mar 29, 2022

It's time for the new puzzler. You're ready. You probably know I have an interesting puzzler. What's more interesting is that we're not sure of the answer, but we will have it.

I remember when I was but a wee lad, going for Sunday drives anywhere in Our Fair City that we would see large tanker trucks loaded with flammable or inflammable fluids.

And they all had somewhere, attached to the underpinnings of this thing from the carriage, a chain or some metal conductive contraption that went from the frame of the vehicle and touched the ground. And it would throw off a shower of sparks as this chain dragged along the ground when the vehicle was in motion.

The question is, part one: what are those big trucks that have these things?

And part B, I will preface the question with the statement that I see these trucks nowadays, but I don't see the chain. So part B is how do they make invisible chains?

Or Part B is, why don't they have them anymore? They used to have them, why? That's part one. And part B, they don't have them anymore. Why?



You know this is normally the time of the show right turn to my haggard, dutiful, respected and sage older brother gently waking him up to ask him if he remembers last week's puzzler.

Now last week's puzzler was the one about the trucks, dragging chains on the ground. And it was a two-parter.

So part one was, why did they drag the chains?

So I had an answer, but it was wrong. Evidently, the problem has nothing to do with when the vehicle is in motion. I thought that the chains were there in fact so that if the vehicle was struck by lightning or some other, static charge would be built up whilst the vehicle was in motion and that sort of thing would constantly be discharged through this ground. That shower of sparks will be directed harmlessly to the earth, terra firma.

However, that's wrong. The problem lies in when the tanker is dispensing its load when it's emptying the vehicle, that the flow of liquid is flammable fluid through the hose, it will actually build up a charge then. And that's why the chain is there.

So nowadays, what they have in order to prevent the static buildup is they have a ground strap that goes from the truck. It's a wire now that they hook up when they put the nozzle into the receptacle that they're filling, like the underground tank or whatever, and that allows the thing to discharge while the fluid is flowing.

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