A bit too much pressure.......

Haze · 2 Jan 2020 at 15:16

So, this happened at work today, the skip is fed by a pressured system, we have a macerater that has a pipe connected too it to suck the waste into this skip, seems something went wrong

JRS · 2 Jan 2020 at 15:20

Well, there's the problem...

SeatIbiza · 2 Jan 2020 at 15:42

Reminds me of that video of a railway (fuel?) tanker imploding on itself. Mighty impressive. Although likely expensive!

touch · 2 Jan 2020 at 15:44

Surely the problem is not enough pressure? Looks like it has imploded? Must have been an impressive force.

Ceryndrion · 2 Jan 2020 at 15:53

Looks like someone turn the switch from suck to blow.

Diddums · 2 Jan 2020 at 15:56

That's an implosion, not an explosion. Must've been one hell of a vacuum to do that.

Actually no, that looks more like a force from above. Going by the location of the dent, I'd say the lorry driver screwed up and did that with his hydraulics.

Haze · 2 Jan 2020 at 16:00

LOL true, I guess it was sucked, no idea how though, onsite we can only turn the air on or off

SeatIbiza · 2 Jan 2020 at 16:03

I always though it was a differential in temperatures that caused this...

I think Diddums seems right though, looks more like an impact.

Jokester · 2 Jan 2020 at 16:04

Nah, that's been done with vacuum - the side is pulled in as well.

Minusorange · 2 Jan 2020 at 16:16

Is it temperature related ?

skyripper · 2 Jan 2020 at 16:18

Somewun dun sucked when dey shoulda blow'd!

Diddums · 2 Jan 2020 at 16:20

Jokester said:
Nah, that's been done with vacuum - the side is pulled in as well.

That was my initial thought too, but then the damage from the top and the way the steel is creased seems to suggest it was struck from above. The sides could easily get pushed in like that in the event of an impact, they're only a few mm thick (we had these exact skips at my last job).

I don't think the top damage is consistent with an implosion.

Kerplunk · 2 Jan 2020 at 16:23

It looks broken

Haze · 2 Jan 2020 at 16:23

Cool vid, love a bit of myth busters

Diddums · 2 Jan 2020 at 16:25

Go take more photos of the scene, we need more info. If anyone asks you wtf you're doing, tell then a bloke on the internet asked you to take photos in return for Haribos. It'll be fine.

Participant · 2 Jan 2020 at 16:26

Looks like that was done by Welsh Anna from university. Ahhh those were the days.

Jokester · 2 Jan 2020 at 16:41

Diddums said:
That was my initial thought too, but then the damage from the top and the way the steel is creased seems to suggest it was struck from above. The sides could easily get pushed in like that in the event of an impact, they're only a few mm thick (we had these exact skips at my last job).

I don't think the top damage is consistent with an implosion.

In fact given the loads this would have been under when the ram was operating, I doubt a vacuum would generate sufficient force. I’m more inclined to say the ram has fouled on something inside and pulled it in from the inside.

arctine · 2 Jan 2020 at 16:42

If you suck the air out of a vessel not built for holding a vacuum, you end up with precisely what is photographed.

If you impact a sealed vessel with enough force to change the shape of it, it will blow outwards before the weakest point releases the pressure inside. There absolutely no way the side walls would crush inwards from impact. Hit any shape of sealed plastic bottle and see for yourself.

arctine · 2 Jan 2020 at 16:43

Jokester said:
In fact given the loads this would have been under when the ram was operating, I doubt a vacuum would generate sufficient force. I’m more inclined to say the ram has fouled on something inside and pulled it in from the inside.

The vacuum doesn't generate any force. The vacuum removes a pressure equilibrium and you would be amazed how little suction is required to do so.

Jokester · 2 Jan 2020 at 16:47

arctine said:
The vacuum doesn't generate any force. The vacuum removes a pressure equilibrium and you would be amazed how little suction is required to do so.

Well, it's the difference in pressure between the outside and inside that generates a force, f=pa after all. But this appears to be a hydraulic crusher, it's going to generate massive pressures inside it presumably, so it's going to be designed to contain that sort of dp.