Bayonet tube heat exchanger

Claim 1

A heat exchanger comprising: a pressure proof cylindrical shell having inlet and outlet nozzles for a first fluid and defining a first fluid space; a first tube sheet connected to said shell to close said first fluid space; a group of bayonet tube outer ducts connected in said shell, one end of each of said outer ducts being closed and another end thereof passing through and being open at said first tube sheet which is secured to one end of said shell; a group of bayonet tube inner ducts inserted in said group of outer ducts, with an annular space being provided between each of said outer and inner ducts and clearance being provided at the closed end of each of said outer ducts to permit each of said inner ducts to communicate with said annular space; only a single inner duct located in only a single outer duct defining each one of a plurality of duct assemblies; a tube side pressure chamber provided in contact with said first tube sheet and which has an outlet nozzle for a second fluid; and a hot gas separation chamber for the second fluid, disposed in said tube side pressure chamber, said hot gas separation chamber having a second tube sheet spaced inwardly from said first tube sheet and from said side pressure chamber, one end of each of said group of inner ducts connected to said second tube sheet and being opened to the inside of said hot gas separation chamber which also communicates with an inlet nozzle for the second fluid through an inlet duct connected to said hot gas separation chamber, the second fluid adapted to be introduced into said hot gas separation chamber and to flow through said inner ducts and said annular space between said inner and outer ducts, thereby exchanging heat with the first fluid; said hot gas separation chamber connected to said side pressure chamber only at said inlet duct of said hot gas separation chamber.