Design of a deep sea water sampler
Hi,
I'm currently designing a device that collects water samples in the ocean. It must withstand 16000 psi. I am having a dispute with my partners.
I believe that if the device is open all the way to the bottom of the ocean, the pressure will remain the same on the inside and outside of the device (No dispute there). Once it is sealed, the pressure will still remain the same. As it rises to the surface, the pressure inside will decrease with the pressure outside, regardless of being sealed. The reason I believe this is because pressure caused by a fluid is due to the displacement of that fluid. Since water is incompressible, not only does it reinforce the walls, but as it rises to the top, it has no affect on the device.
My partners believe either one of the two following options:
Option 1: Once it is sealed, the pressure outside will be greater than the pressure inside.
Option 2: Once it is sealed, the pressure will remain the same inside and outside, but as it rises, the pressure inside remains at 16000 psi, but the pressure outside will decrease as the depth decreases.
The only reason I don't believe option 2 is because water is incompressible. PV = mRT is the only equation regarding the relationship between Pressure, Volume, and Temperature. Unfortunately, it doesn't work on water since as I stated several times, water is incompressible.
Can some one give me any insight on this?