As a milk hauler, I have to say I saw this happen first hand at a milk plant. Luckily it didn’t happen to me, and you can’t help but feel bad for the person that it did happen to.
I don’t know what material these tanks in this video were made of, but I would guess steel, the way they held up until the sudden collapse.
You can believe that’s no trick. I was standing in the bay talking to some other drivers, when the receiver, new to the job, apparently forgot to vent the tanker before starting the pump.
These are high capacity and high speed pumps designed to unload 6500 gallons in about 15 minutes. As the liquid is pulled from the tanker, it creates a vacuum and unless it’s vented will suck that tank down.
To give you a good example, take a plastic drink bottle and after you have finished drinking what was in it, put your mouth over the end and suck all the air out of the bottle.
What Happens? You just did what you saw in the video. Unlike the truck though, you can blow air back into the bottle and restore it back to normal with only a few kinks.