Purge gas system for aircraft

Claim 1

IN A PURGE GAS GENERATING SYSTEM, MEANS PROVIDING A CASING HAVING AN AIR INLET END AND AN AIR OUTLET END, MEANS FOR BURNING A FUEL-AIR MIXTURE TO FORM HOT PRODD, UCTS OF COMBUSTION, FIRST HEAT EXCHANGE MEANS CONNECTED TO RECEIVE PRODUCTS OF COMBUSTION FROM SAID BURNER MEANS FOR EXCHANGING A PORTION OF THE HEAT FROM SAID PRODUCTS OF COMBUSTION TO AN AIR STREAM, SAID BURNER MEANS AND SAID FIRST HEAT EXCHANGE MEANS BEING DISPOSED AS A UNIT IN SAID CASING ADJACENT THE OUTLET END THEREOF, MEANS FORMING A FIRST TUBE BUNDLE HEAT EXCHANGER WITH THE TUBES THEREOF EXTENDING TRANSVERSELY OF SAID CASING AT A POSITION ADJACENT TO SAID FIRST HEAT EXCHANGE MEANS BUT CLOSER TO SAID CASING INLET THAN SAID FIRST HEAT EXCHANGE MEANS, CONDUCT MEANS CONNECTED FOR CONDUCTING PRODUCTS OF COMBUSTION FROM THE FIRST SAID HEAT EXCHANGE MEANS TO FLOW THROUGH THE TUBES IN SAID TUBE BUNDLE, MEANS FORMING SECOND, THIRD AND FOURTH TUBE BUNDLE HEAT EXCHANGERS IN SIDE BY SIDE REALTIONSHIP IN SAID CASING AT A POSITION BETWEEN SAID CASING INLET AND THE TUBES OF SAID FIRST TUBE BUNDLE HEAT EXCHANGER, MEANS FORMING SEPARATE CLOSED SPACES AROUND THE TUBES IN SAID SECOND, THIRD FOURTH TUBE BUNDLES, ALL OF THE TUBES IN SAID SECOND, THIRD AND FOURTH TUBE BUNDLES BEING PARALLEL AND EXTENDING LONGIUTUDINALLY OF SAID CASING SO THAT AIR FLOWING THROUGH SAID CASING FROM SAID INLET TO SAID OUTLET PASSES FIRSTLY THROUGH THE TUBES IN SAID SECOND, THIRD AND FOURTH TUBE BUNDLES, SECONDLY ACROSS THE TUBES IN SAID FIRST THE BUNDLE, AND THIRDLY THROUGH SAID FIRST HEAT EXCHANGER, INTERCONNECTING CONDUIT MEANS BETWEN THE TUBES OF SAID FIRST TUBE BUNDLE AND THE ADJACENT ENDS OF THE CLOSED SPACES AROUND THE TUBES IN SAID SECOND AND THIRD TUBE BUNDLES, MEANS CONNECTING THE OPPOSITE ENDS OF THE LAST SAID CLOSED SPACES TO THE MOST ADJACENT END OF THE CLOSED SPACE AROUND THE TUBES IN THE FOURTH SAID TUBE BUNDLE, A GAS OUTLET FITTING, MEANS CONNECTING THE OPPOSITE END OF THE LAST SAID CLOSED SPACE TO SAID OUTLET FITTING, MEANS FORMING AN AIR BYPASS CONNECTED BETWEEN THE CASING ADJACENT THE TUBES IN THE FIRST SAID TUBE BUNDLE AND SAID CASING INLET, DAMPER MEANS DISPOSED IN SAID CASING BETWEEN SAID SECOND, THIRD AND FOURTH TUBE BUNDLES AND THE BYPASS CONNECTION TO SAID CASING, MEANS SENSITIVE TO THE AIR TEMPERATURE WITHIN SAID CASING AT A POINT BETWEEN SAID SECOND, THIRD AND FOURTH TUBE BUNDLES AND SAID DAMPER MEANS, AND MEANS CONNECTED TO SAID DAMPER MEANS FOR CLOSING THE LATTER AS SAID TEMPERATURE SENSITIVE MEANS COOLS TOWARD A PREDETERMINED LEVEL AND FOR OPENING SAID DAMPER MEANS AS THE TEMPERATURE OF SAID TEMPERATURE SENSITIVE MEANS RISES ABOVE SAID LEVEL.