An outflow valve is disclosed for use in a pressure vessel. The outflow
valve includes a dual wall valve housing having a central bore, a
butterfly plate assembly and an angled drive shaft. The butterfly plate
assembly is designed to fit and rotate within the central bore. The
angled drive shaft has first and second ends rotateably coupled to the
dual wall valve housing, and the angled drive shaft is attached to the
butterfly plate. The drive shaft is designed to rotate the butterfly
plate assembly between a closed position and an open position within the
central bore.