Abstract: A heat exchanger (10) comprising a plurality of plastic tubes (12) arranged in a series of mutually parallel rows and a pair of plastic collector plates (14) bonded to the respective ends of the said tubes (12). Each collector plate (14) is formed by a plurality of plastic terminal elements (22), each of which has at least one set of semicircular seats (24 and 26) suitable for receiving the ends of a row of tubes (12). The said semicircular seats (24 and 26) of each terminal element (22) are separated from each other by bonding portions (28 and 30) suitable for welding to the corresponding bonding portions of a complementary terminal element along a welding plane (34).

Abstract: A heat exchanger comprising plates of thermoplastic tubes arranged in a way which minimizes the thermal resistance at the outer surface of the tubes preferably to not more than 5 times the resistance to heat transfer at the inside of the tubes. The tubes are arranged in the tube plates in groups that can be flat or slightly wavy, such as undulating in a periodic manner, or offset with open spaces facing groups of tubes in alternating rows. This is done in a way that maximizes turbulence outside the tubes and minimizes vortices which can trap coolant in the interstices between tubes.