Vapor generator

Claim 1

A VAPOR GENERATOR OPERATING ON THE DOUBLE REHEAT CYCLE AND HAVING THE CHARACTERISTIC THAT THE PERCENTAGE OF THE TOTAL HEAT ABSORPTION OF THE UNIT WHICH IS ACCOUNTED FOR BY THE HIGH PRESSURE REHEAT INCREASES WITH DECREASE IN LOAD FROM THE MAXIMUM LOAD WHILE THE PERCENTAGE ACCOUNTED FOR BY THE LOW PRESSURE REHEATER DECREASES AS THE LOAD IS DECREASED FROM THE MAXIMUM AND INCLUDING A FURNACE HAVING PRIMARY FLUID CARRYING TUBES ON ITS WALLS, MEANS INTRODUCING FUEL AND AIR INTO SAID FURNACE, SAID MEANS BEING OPERATIVE TO ADJUST THE ZONE OF COMBUSTION IN THE FURNACE TOWARDS AND AWAY FROM THE FURNACE OUTLET, HIGH PRESSURE REHEATER MEANS AND LOW PRESSURE REHEATER MEANS DISPOSED IN THE COMBUSTION GAS PATH IN SERIES WITH REGARD TO COMBUSTION GAS FLOW WITH THESE REHEATER MEANS BEING LOCATED SUCH THAT THE LOW PRESSURE REHEATER IS EFFECTED PRIMARILY BY THE CHARACTERISTICS OF THE COMBUSTION GAS STREAMS AT A LOCATION DOWNSTREAM OF THE HIGH PRESSURE REHEATER MEANS, MEANS OPERATIVE TO RECIRCULATE COMBUSTION GASES TO THE FURNACE IN A MANNER TO INCREASE THE HEAT CONTENT OF THE GASES WITH AN INCREASE IN THE QUANTITY OF GASES RECIRCULATED AND MEANS FOR CONTROLLING THE ADJUSTMENT OF THE ZONE OF COMBUSTION PREDOMINANTLY IN RESPONSE TO THE HIGH PRESSURE REHEATER TEMPERATURE WITH VARYING LOAD AND MEANS FOR SIMULTANEOUSLY CONTROLLING THE RECIRCULATION OF GASES TO THE FURNACE PREDOMINANTLY IN RESPONSE TO THE LOW PRESSURE REHEATER TEMPERATURE.