(05122012) Project Update

pvc piping and fittings.

• 4 10ft pvc pipes (3/4 in. diameter)
• 2 elbows
• 3 couplers
• 2 caps
• 2 male adapters with threadings
• pvc cement and primer

Connecting the pieces:
We found that the pipe is not entirely rigid when 30+ feet of tubing is connected.  It bends significantly.  We will definitely need strong support for the pipes when not able to hold against a tall building.

Testing a vacuum:
We have been informed that placing a cap on the top end of a pipe filled with water would create a sufficient vacuum.  We tested this by capping one end, filling the pipe with water, and then capping the top.  We used teflon tape on the threadings of the end of the pipe that was suppossed to seal a vacuum.  We then removed the cap on the bottom of the pipe and the water came right out.  This repeated a couple times each trying to adjust the integrity of the vacuum.

We proceeded to experiment with a test analogous to a drinking straw, in that we used the palms of our hands to create a seal.  This didn't work either, it also wouldn't lift water out of a small pitcher of water.

Just before, we tried two ways to do this with an actual drinking straw:

• One way was having one end of the straw submerged under water and placing a thumb over the air exposed top end.  After lifting the straw, the water was "stuck" in the straw as expected.  
• Method two, closer to our pvc experiment, was to place one finger over the bottom of the straw, fill the straw with water from the top, place a thumb over the top and then release the finger from the bottom - the water remained in the straw.  So, it doesn't matter if the straw end is submerged under water to keep a vacuum (according to the small scale experiment).

Volume of water:
We found that the 3/4 in diamater (although marked as such) measured to be 14/16 in. and is 120.5 inches long.  One piece of tubing is filled with about 1.3 L of water.  That comes out to about 4.4 L of water if the tube is filled to a depth of 34 feet. 

Next Goal:
First phase of the pressure chamber:

• Complete lid assembly
• connect piping
• fill water through top

Second phase:

• create path for sensor wiring, or
• determine feasibility of remote signaling
• create method of users to preserve water in piping and allowing removal of lid**