Abstract: A heat exchanger for heat exchange between a first and a second fluid and comprising a cylindrical casing 2, a cylindrical fluid conduit 5 arranged inside the casing such that an axially extending tubular space 8 is defined, at least one helical coil 9, 10 of a finned or corrugated tube being arranged inside the tubular space, and adjustable throttle means 17, 17a, 18 adapted and arranged for adjustably throttling flow of the first fluid through the conduit 5 to adjust the flow of the first fluid through the conduit and the first tubular space for adjusting the heat exchange between the first fluid and the second fluid flowing through the helical coils 9, 10.

Abstract: A heat-exchanger unit (13) for recovering heat from the flue gases from a cylinder steam boiler (10), said heat exchanger unit comprising a flue-gas tube (14) and a heat-exchanging tube (16) which is supported concentrically inside the flue-gas tube (14) by a bent inlet pipe (19) extending from a lower opening (20) in the peripheral wall of the flue-gas tube (14) to an inlet opening (21) in a lower outwardly bulging end wall (22) of the heat-exchanging tube (16), and an outlet pipe (23) extending from an outlet opening (24) in an upper part of the peripheral wall of the heat-exchanging tube (16) to an upper opening (25) in the peripheral wall of the flue-gas tube (14). The inlet pipe (19) has a first, horizontal, straight end portion (19A), a second, upwardly directed, straight end portion (19B) and also an intermediate, curved portion (19C). The bending angle (.alpha.) of the curved portion exceeds 90.degree. and the other end portion (19B) extends with an inclination determined by said bending angle (.

Abstract: A self-regulating exhaust gas boiler intended for the recovery of thermal energy from the exhaust gases of diesel engines or the like, has a steam/water cylinder acting as the water and steam space. There is a convection part acting as the vaporizer and being fitted in the vertical orientation between the steam/water cylinder and a lower cylinder, or the like, and connected to it. There is at least one downcomer interconnecting the steam/water cylinder and the lower cylinder, or the like. At least one valve or corresponding device regulates the amount of water and the water level in the convection part is mounted between the steam/water cylinder and the lower cylinder, or the like, preferably in the lower section of the downcomer.