Heat exchanger

Claim 1

A heat exchanger having at least three tubes (1, 2, 3, 4) of thermally conductive material arranged coaxially within one another in a nest, and spaced radially from one another, the spacing between said nested tubes defining fluid medium flow chambers (5, 6, 7); means (18, 19; 15) for introducing at least two heat exchange media in the heat exchange medium flow chambers formed between the tubes; at least one distributor head (8, 45) coupled to said tubes to form, with the tubes, an axially coupled unit and to provide a flow connection for the heat exchange media as well as an end retaining means for the tubes, said tubes and the heads being coupled in fluid-tight manner, the heads (8) being formed with an inner space communicating with the chambers (5, 6, 7) between the tubes (1, 2, 3, 4), wherein, in accordance with the invention, each distributor head (8, 45) has two substantially cylindrical walls (9, 10; 46, 47) concentric with respect to each other and radially spaced within one another, defining a substantially annular chamber (11) between said walls, said walls being integrally connected; an end wall (9a) extending transversely from the outer wall (9) and defining therebeneath an end chamber (17, 50), said end chamber communicating with the essentially annular chamber (11), said end chamber extending inside the outer wall (9) over the entire radial cross section of the outer wall; means (20, 21, 23) for sealingly securely and releasably coupling the outer wall (9, 46) to the outermost (1) of said plurality of tubes forming the nest of tubes, said coupling means generating an axial clamping force between said outer wall (9, 46) of the head (8, 45) and said outermost tube (1); a first stop (24) formed on the inner wall (10); a second inner tube (2) of said plurality of tubes being inserted into said inner wall (10, 47) and fitting against said axial stop; a second stop (28) positioned axially closer to said transversely extending end wall (9a) than said first stop formed in the inner wall (10, 47); a hollow-cylindrical sleeve (26; 58, 59) positioned with said inner wall, axially retained against said second stop, and spaced radially from the inner wall (10), said sleeve having an inner chamber (34) communicating with the end chamber (17) and defining, between the outer wall of the sleeve and the inner wall (10) of the head, an inner chamber (16); a third tube (3) of said nest of tubes, located radially spaced within said second tube (2) and sealingly connected to said sleeve (26; 58, 59), said inner chamber (16) communicating with a second chamber (6) formed by the radial spacing between the second and third tubes (2, 3); a radially extending connecting portion (14) between said inner (10) and outer (9) walls of the head (8); and a radial flow connection (15, 60) in said connecting portion (18) extending, without fluid communication, across the part-annular chamber (11) to provide for flow communication to the second chamber (6) formed between the second and third tubes (2, 3) for fluid flow through said second flow chamber by another heat exchange medium.