First compression test

A dozen of type “3” bottles were filled with 6 gr. of dry ice and sealed with Teflon tape around the threads and duct tape around the cap. Measurements of their mass and max. diameter where taken so leakage can be determined. Three days later the measurements were repeated and the bottles showed an average leakage of 0,2%. 

Placing the bottles in the safety container

Afterwards, the bottles were placed in the safety container, in a hexagonal pattern, and were tested under compression. The bottles behaved surprisingly well but the test was not completed because the screws holding the Plexiglas sheet on the safety container were starting to fail. After having been loaded with a force of 20KN (2000kg) and having as a system around 8cm of displacement, the bottles returned to their previous condition once the force was removed, and no bursting took place, nor were they plastically deformed. The bottles situated at the upper 2 rows, in fact, remained intact. Some of the bottles at the lower 2 rows presented minor scratches along the contact points with the adjacent bottles, due to friction, but not severe fissures in any case.

2000 kg on the bottles only caused minor scratches

 After the compression test was competed, the bottles’ mass was re-measured. The bottles at the top 2 rows had no leakage, yet, the ones at the bottom had an average leakage of 0.17%. The measurements on CO2 leakage indicated that the sealing method needs to be optimised in order for the bottles to remain long-term rigid.

Mass measurements to determine C02 leakage