Reinforced Bottle Testing – 2L@180psi

Work has commenced on reinforcing 2L bottles to increase thrust on the water rocket car.

The first attempt to make a 2L reinforced bottle uses
– 1 x 2L bottle (slightly shrunk)
– 2 x 2.25L bottles

The 2L and 2.25L bottles have the same diameter, the 2.25L is slightly taller though. The  2L bottle was slightly shrunk in hot water to reduce its diameter so the 2.25L would slide over the top of it. One of the 2.25L bottles had the top 1/3 cut off. The other 2.25L bottle had the bottom 1/3 and the the bottle throat section removed.

Then 2.25L bottle without the top was then slid over the bottom section of the 2L carefully lining up the claws at the base. The second 2.25L we had to cut a bit more of the throat away to fit it over the 2L bottle throat flange (for want of a better word). The 2 x 2.25L bottles overlap a little in the middle. It was then just taped this down with fibre reinforced tape to hold all the sections in place

Standard 2L (left) and 2L reinforced (right) bottles.

Reinforced bottle on its side

The bottle was then ready to be hydrostatically tested. A few modifications for safety were made (due to the higher test pressures) to the air hose to hold the hose and connectors in place in case the air hose exploded. Each separate section of hose was cable tied to a brick

Pump to airhose connection hold-down

Airhose to abort valve hold-down

The bottle itself was placed in a milk crate with a 20L water container (full) placed on top to hold it down in case the bottle exploded as a safety cage.

Bottle Testing Cage

There is a valve in the female gardena connector that will close off the airhose if it has pressure in the line but no bottle on the open end. This makes it easy to test the air hose itself for leaks. Safety glasses were put on and the air hose (no bottle) was pressure tested up to 180psi with no leaks. This is the pressure we decided we wont test past until the airhose, connectors and PVC abort valve are replaced with stronger components.

Safety glasses were put on again and the reinforced bottle was filled with water and pressurized to 180psi. There were a few drips from the nozzle (only hand tightened) but the bottle held the pressure fine.

Reinforced bottle hydrostatic test to 180psi

The next version of the reinforced bottle we will grind of the flange of the 2L so that the throat section is more reinforced and use PL Premium to glue the bottle sections together.

The test was very successful, this is the highest pressure we have pressurized a bottle to. It seemed the reinforced bottle could take a lot more pressure before bursting as there was minimal (visually) stretching of the bottle. We are working on replacing the components for the air delivery and will try a further hydrostatic test once these are in place.

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This entry was posted on Wednesday, June 2nd, 2010 at 11:06 pm and is filed under Development. You can follow any responses to this entry through the RSS 2.0 feed. Both comments and pings are currently closed.


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