Can a Glass Pressure Vessel Demonstrate Crush Depth with a Bike Pump?

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In summary, the conversation discusses the idea of rigging up a glass pressure vessel to demonstrate crush depth using Styrofoam objects. However, it is deemed unsafe and not advisable to use glass as the material for the vessel due to the high pressure involved. Suggestions are made to use a plastic jug or a pressure cooker instead. The goal is to recreate the well-known demonstration of how a Styrofoam cup shrinks under pressure, and potentially use it as part of an installation in a museum.
  • #1
Gersty
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I'd like to rig up a glass pressure vessel to see if I could demonstrate crush depth and stuff like that. I was sort of picturing a large small-necked glass jug (think water cooler jug) filled with water and attached to a compressor (or maybe even bike pump?). Styrofoam objects would be inserted, weighted down so they are suspended near the middle of the water, the top sealed, the vessel pressurized, etc...
I've seen demos like this done with Styrofoam beads in a plastic bottle filled with air pressurized with a bike pump. Since liquids aren't compressible, would filling the glass container with water first make it impossible to reach sufficient pressure?
Thoughts?
Safe?
Fittings?
Could enough pressure be generated with a bike pump?
 
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  • #2
"Rigging up" something to demonstrate "crush depth" with Styrofoam is not safe.
You need to use known pressures, equipment that is rated for those pressures, and procedures for maintaining and operating that equipment that are well thought out.

A quick web search shows you can do this safely with a pressure cooker.
 
  • #3
Why use glass? Just use a plastic jug with weights, and lower it into the school pool to show how it crushes when filled with air, but does not crush when filled with water...
 
  • #4
Thanks .Scott for the quick reply. I know fiddling around with pressurized containers isn't the safest. I wasn't sure how high the pressure would need to be to achieve measurable results on something like a styrofoam cup. The demo needs to be visible which is why I thought a large relatively thick glass jug would work.I have seen demos like this that use styrofoam beads in a plastic water bottle pressurized with a bike pump but wondered if filling with water would be doable.
 
  • #5
Oh, I misread your post. You want to pressurize a glass jug. I agree with @.Scott that is a bad idea. Don't you have a pool available?
 
  • #6
Nope. No pool available. I'm trying to sort of duplicate that demo we've all seen where a styrofoam cup is attached to the outside of a submarine. The sub dives and returns to the surface. When the sub returns to the surface the cup has shrunk due to the pressure at depth.
I'd like to build an apparatus to demonstrate this as part of an installation on a submarine at a museum. I picture kids decorating their little cups and then placing them in the vessel which seals (autoclave or pressure cooker style) and they watch as pressure is increased till the cup (which is visible) begins to compress. The vessel opens and the kids have a souvenir and hopefully some interest in finding out more.
 
  • #7
Gersty said:
I picture kids decorating their little cups and then placing them in the vessel which seals (autoclave or pressure cooker style) and they watch as pressure is increased till the cup (which is visible) begins to compress.
The results from 2000 psi:
cups_545.jpg

http://oceanexplorer.noaa.gov/explorations/deepeast01/logs/sep14/media/cups.html

Even at half that pressure, an unplanned release could sent you pressure vessel rocketing across the room.
 

1. What is crush depth?

Crush depth is the maximum depth that a submarine or other underwater vessel can withstand before the external pressure causes it to collapse.

2. How is crush depth determined?

Crush depth is determined by various factors such as the design and construction of the vessel, the materials used, and the depth and pressure of the surrounding water. It is usually determined through extensive testing and calculations by engineers and naval architects.

3. What happens to a submarine at crush depth?

At crush depth, the external pressure on the submarine becomes too great for it to withstand, causing it to collapse and implode. This can lead to the destruction of the vessel and, in most cases, the loss of all crew members on board.

4. Can a submarine survive crush depth?

It is highly unlikely for a submarine to survive crush depth. However, some modern submarines are designed to withstand greater depths and have advanced technology to help them withstand the pressure. Even then, it is still dangerous and risky for a submarine to go beyond its designated crush depth.

5. How is crush depth demonstrated?

Crush depth can be demonstrated through various means such as computer simulations, physical testing, and field trials. These demonstrations involve subjecting the vessel to increasing pressure until it reaches its designated crush depth, or until it collapses. However, it is important to note that these demonstrations are done under controlled and safe conditions, and should not be attempted in real-life situations.

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