A heat exchanger includes: a casing into which heating gas is supplied; and a plurality of heat transfer tubes which are arranged in the casing, wherein the plurality of heat transfer tubes are set in a posture in which a plurality of straight tube portions are arranged in a direction intersecting a heating gas flow direction, are stacked a plurality of stages in the heating gas flow direction, and are distinguished into first and second heat transfer tubes respectively located on an upstream side and a downstream side in the heating gas flow direction, and wherein the second heat transfer tube is formed so that an outer diameter of the tube and an arrangement pitch of the plurality of straight tube portions are smaller than those of the first heat transfer tube.

A heat exchanger includes a tube expansion portion provided on a heat transfer tube such that an outer peripheral surface of the heat transfer tube is pressed against an inner peripheral surface of a first hole provided in a side wall portion of a case, and a first concave surface portion that is provided in a part of an outer surface of the tube expansion portion and forms a first gap, into which brazing material of a first brazed portion advances, between the outer surface of the tube expansion portion and the inner peripheral surface of the first hole. Thus, the attachment strength of the heat transfer tube can be improved by means of a simple configuration.

The heat exchange device (200) includes a primary heat exchanger (10), a secondary heat exchanger (20), and a connecting pipe (60). The connecting pipe connects the primary heat exchanger and the secondary heat exchanger. The primary heat exchanger (10) includes a primary heat exchange part (11), a shell plate (12) surrounding the primary heat exchange part, and a body pipe part (13) for cooling the shell plate. The body pipe part (13) is disposed closer to a burner than the primary heat exchange part (11) and is connected to the connecting pipe (60). The primary heat exchange part (11) includes a first heat transfer tube part (111) connected to the body pipe part (13), and a second heat transfer tube part (112) connected to the first heat transfer tube part and disposed on a side opposite to the body pipe part with respect to the first heat transfer tube part.

The heat exchange device (200) includes a primary heat exchanger (10), a secondary heat exchanger (20), and a connecting pipe (60). The connecting pipe connects the primary heat exchanger and the secondary heat exchanger. The primary heat exchanger (10) includes a primary heat exchange part (11), a shell plate (12) surrounding the primary heat exchange part, and a body pipe part (13) for cooling the shell plate. The body pipe part (13) is disposed closer to a burner than the primary heat exchange part (11) and is connected to the connecting pipe (60). The primary heat exchange part (11) includes a first heat transfer tube part (111) connected to the body pipe part (13), and a second heat transfer tube part (112) connected to the first heat transfer tube part and disposed on a side opposite to the body pipe part with respect to the first heat transfer tube part.

A condensing combustion apparatus comprising: an upward combustion burner (20); a sensible-heat exchanger (40) which absorbs sensible combustion heat generated by the burner (20); and a latent-heat exchanger (50) which absorbs latent heat of steam included in a combustion gas which has passed the sensible-heat exchanger (40), wherein the sensible-heat exchanger (40) and the latent-heat exchanger (50) have the same lateral widths and are configured as fin-tube heat exchangers having common structures, and wherein a flow path through which the combustion gas, which has passed the sensible-heat exchanger (40), flows upward is formed on one side portion of the latent-heat exchanger (50), a flow path through which the combustion gas, which has passed the one side portion of the latent-heat exchanger (50), flows downward corresponding to a direction in which condensed water falls is formed on a middle portion of the latent-heat exchanger (50), and a flow path through which the combustion gas, which has passed the middle portion of the latent-heat exchanger (50), flows upward and discharges is formed on another side portion of the latent-heat exchanger (50).

A condensing combustion apparatus comprising: an upward combustion burner (20); a sensible-heat exchanger (40) which absorbs sensible combustion heat generated by the burner (20); and a latent-heat exchanger (50) which absorbs latent heat of steam included in a combustion gas which has passed the sensible-heat exchanger (40), wherein the sensible-heat exchanger (40) and the latent-heat exchanger (50) have the same lateral widths and are configured as fin-tube heat exchangers having common structures, and wherein a flow path through which the combustion gas, which has passed the sensible-heat exchanger (40), flows upward is formed on one side portion of the latent-heat exchanger (50), a flow path through which the combustion gas, which has passed the one side portion of the latent-heat exchanger (50), flows downward corresponding to a direction in which condensed water falls is formed on a middle portion of the latent-heat exchanger (50), and a flow path through which the combustion gas, which has passed the middle portion of the latent-heat exchanger (50), flows upward and discharges is formed on another side portion of the latent-heat exchanger (50).

A high temperature fluid generator is configured to heat a fluid (e.g. water; thermal oil or the like) to a high temperature (e.g. greater than 250 degrees Fahrenheit or 120 degrees Celsius) using a fuel-burning furnace. The generator generally comprises a furnace module, wherein fuel is burned, and a convection module where the combustion gases are put in contact with a series of fluid-bearing convection tubes. The furnace module comprises a series of fluidly interconnected headers, some of which are also fluidly connected to the convection tubes in the convection modules. The various headers contribute to the overall structure of the generator. The convection tubes are arranged into at least two bundles which are movably mounted in the convection module of the generator such to be movable in and out of the convection module for inspection, cleaning, maintenance and/or repair.

A high temperature fluid generator is configured to heat a fluid (e.g. water; thermal oil or the like) to a high temperature (e.g. greater than 250 degrees Fahrenheit or 120 degrees Celsius) using a fuel-burning furnace. The generator generally comprises a furnace module, wherein fuel is burned, and a convection module where the combustion gases are put in contact with a series of fluid-bearing convection tubes. The furnace module comprises a series of fluidly interconnected headers, some of which are also fluidly connected to the convection tubes in the convection modules. The various headers contribute to the overall structure of the generator. The convection tubes are arranged into at least two bundles which are movably mounted in the convection module of the generator such to be movable in and out of the convection module for inspection, cleaning, maintenance and/or repair.

A heat exchanger includes a plurality of heat transfer tubes extending in a first direction and aligned in a second direction intersecting with the first direction, and a plurality of fins disposed in the first direction. The fins each include a plurality of fin main bodies aligned in the second direction, and a bridging portion connecting two adjacent ones of the fin main bodies. At least one of the fin main bodies is provided with a through hole next to the bridging portion in the second direction.

A heat exchanger includes a tube expansion portion formed by expanding a heat transfer tube so that an outer peripheral surface of the heat transfer tube is pressed against an inner peripheral surface of a hole provided in a side wall portion of a case. The tube expansion portion includes first and second bulge portions positioned respectively on the inside and the outside of the side wall portion so as to sandwich the side wall portion in an axial length direction of the heat transfer tube and configured such that respective outer peripheral surfaces thereof partially bulge outward in a radial direction of the heat transfer tube, an end portion tip end of the heat transfer tube is positioned apart from the second bulge portion, and the end portion tip end and a part in the vicinity thereof are expanded so as to be included in a part of the tube expansion portion. Thus, effects such as improving the precision with which the side wall portion of the case, the heat transfer tube, and a connecting tube are fitted to each other can be achieved, and as a result, the respective parts can be brazed easily and appropriately.