Force exchange wheel - a modyfied vanepump, put under water

[Low-Q]

I have seen these vane pumps, or something which is similar (http://www.youtube.com/watch?v=qJ1QccN7LXg&feature=related). Take this pump but modify it a bit.
This pump have lots of plates which is going in and out from an excentric rotor inside a chamber. These plates will make a pocket between them, with greater surface area on one side than the other. So by applying high pressure to each "pockets" which are made between those plates, these plates are forced to move in the direction where there are greater plate area.

What if we put a big pump like this into the water, but angle the pump on the video 90 degrees, so the greatest volume is on the right side. The water intake at the bottom are almost 180 degrees from left to right, and the exit are almost 180 degrees from right to left. Between intake and exit, there are a sealed part. The weight of the water are the same regardless of pressure. What will happen when the "deep sea" high pressure enters the pockets at the bottom to force rotation, and let the water exit the upper part which is right under sea level at less pressure?

I will try to make a drawing of the idea, but the basic idea is that pressure will force the pump to rotate because of the difference in surface area on each side of each pocket. Look away from friction as I am only looking for the forces that are made by the pressure, and the pressure difference

Any thoughts, alternative ideas, or comments to this?

EDIT: Picture attached. Water intake and exit are changed some.

Vidar