Gas turbine engine fixed boundary recuperator

Claim 1

A GAS TURBINE ENGINE COMPRISING: AN ELONGATE CASING HAVING AN AIR INLET AT ONE END AND AN EXHAUST OPENING AT THE OTHER END; A GAS TURBINE POWER UNIT WITHIN SAID CASING AND HAVING AN EXHAUST PASSAGE COMMUNICATING WITH SAID EXHAUST OPENING AND FURTHER HAVING AN AIR INTAKE; A WALL WITHIN SAID CASING ABOUT SAID POWER UNIT AND SPACED INWARDLY FROM SAID CASING TO DEFINE WITH THE LATTER A GENERALLY ANNULAR AIR INLET PASSAGE COMMUNICATING AT ONE END WITH SAID AIR INLET OF SAID CASING AND AT THE OTHER END WITH SAID AIR INTAKE OF SAID POWER UNIT, SAID INLET PASSAGE ENCIRCLING SAID POWER UNIT AND EXTENDING SUBSTANTIALLY THE FULL LENGTH OF SAID CASING IN DIRECT HEAT TRANSFER RELATION TO THE CASING, WHEREBY INLET AIR FLOWING THROUGH SAID INLET PASSAGE COOLS SAID CASING; A HEAT EXCHANGER WITH SAID OTHER END OF SAID CASING HAVING FIRST PASSAGE MEANS AND SECOND PASSAGE MEANS THROUGH WHICH SAID EXHAUST PASSAGE OF SAID POWER UNIT COMMUNICATES WITH SAID EXHAUST OPENING, AND THIRD PASSAGE MEANS THROUGH SAID SAID OTHER END OF SAID ANNULAR INLET PASSAGE COMMUNICATES WITH SAID AIR INTAKE OF SAID POWER UNIT, SAID FIRST PASSAGE MEANS AND SAID THIRD PASSAGE MEANS BEING DISPOSED IN HEAT TRANSFER RELATION, WHEREBY THE INLET AIR ENTERING SAID POWER UNIT IN PREHEATED BY EXHAUST GASES FLOWING THROUGH SAID FIRST PASSAGE MEANS; AND MEANS FOR PROPORTIONING EXHAUST GAS FLOW FROM SAID POWER UNIT THROUGH SAID FIRST AND SECOND PASSAGE MEANS, THEREBY TO REGULATE PREHEATING OF THE INLET AIR ENTERING SAID POWER UNIT.