is opened purging the primary inner manifold 102 and primary inner port 101 with inert gas 123 fig8 illustrates an example of the alignment of the system 100 when the primary inner port 101 is receiving a blend of fuel from the first and second gas supplies 120 and 122 the va 13 15 valve is closed pressurizing the inert gas buffer 116 with inert gas 123 the vah 1 2 valve is closed the vgc 4 valve is opened allowing fuel from the first gas supply 120 to flow to the primary inner manifold 102 the vs 4 12 and vgc 12 valves are opened allowing fuel from the second gas supply 122 to flow to the primary inner manifold 102 and mix with the fuel from the first gas supply 120 the mixed or blended fuel flows to the primary inner port 101 fig9 illustrates an example of the alignment of the system 100 when the system is in a u201c tripped u201d or secured mode in the illustrated example the vent valves including the vent valves va 13 31 and va 13 27 are opened the valves controlling the flow of the inert gas 123 including the valve vah 1 4 are opened allowing inert gas 123 to purge and vent through ports 101 and 103 and to purge and vent from the inert gas buffers 116 and 118 the valves controlling the flow of fuel and cpd air 113 are closed while the invention has been described in detail in connection with only.