Currently, oxygen cylinders installed in an aircraft require refilling once to three times per production cycle for testing the oxygen system. Refilling a cylinder requires removal from the aircraft, transportation to the fill shop, performing the filling operation, returning to the aircraft, reinstallation, and retesting the oxygen system. Opportunity exist for damaging cylinders and contamination of the oxygen system along with adding a recurring potential for mistakes in the removal and installation of the cylinders and pressurization and depressurization of the system.
A novel tool was developed to eliminate this lengthy and potentially hazardous way of working. Using the newly defined tool, oxygen cylinders no longer need removal from the aircraft. Only the pressure regulator must be removed from the cylinder assembly and the tool and fill cart attached to the cylinder, while remaining in its installed position. This process saves time and money as well as increases safety, both for personnel as well as for equipment.
The tool is an assembly of existing qualified aircraft oxygen system parts and a pressure relief valve connected with copper based tubing. It is designed to minimize the potential fire hazard due to adiabatic compression heating during the filling operation.