Abstract: A heat exchanger includes a plurality of heat transfer tubes housed in a predetermined case, a connecting tube body for connecting the plurality of heat transfer tubes, a predetermined tube expansion portion provided on each heat transfer tube, a first peripheral wall portion provided on the tube expansion portion, and a second peripheral wall portion that is positioned on an end portion of the connecting tube body and fitted to the tube expansion portion, wherein the first and second peripheral wall portions have different sectional shapes and are fitted together in a partial contact state including predetermined contact and non-contact portions. According to this configuration, the heat transfer tubes can be fixed to a side wall portion of the case and the connecting tube body can be connected to the heat transfer tubes easily and appropriately.

Abstract: A metal bend pipe having a bend portion bent in a semi-circular arc shape is provided, in which an identification part that enables one of the two end portions of the bend portion to be identified as the bending-start side or the bending-end side is provided, and the identification part is integrally formed as a protruding and/or recessed three-dimensional region. Thus, it is possible to easily and reliably identify which of the two end portions of the bend portion is the bending-start side or the bending-end side.

Abstract: A tank includes: a bowl-shaped head having a peripheral wall whose base end side is open; and a tubular body member having an end in an axial length direction joined to the head. The peripheral wall of a region of the head close to a base end is an inclined peripheral wall whose inner diameter increases toward the base end. The end of the body member is inserted inside the inclined peripheral wall of the head and is joined to an inner peripheral surface of the inclined peripheral wall via a weld. A mark available for use in determining a position of the end of the body member is provided in a position on an outer peripheral surface of the body member on a central part side of the body member in the axial length direction with respect to the head and away from the end by a predetermined dimension.

Abstract: A heat exchanger includes a plurality of heat transfer tubes housed in a predetermined case, a connecting tube body for connecting the plurality of heat transfer tubes, a predetermined tube expansion portion provided on each heat transfer tube, a first peripheral wall portion provided on the tube expansion portion, and a second peripheral wall portion that is positioned on an end portion of the connecting tube body and fitted to the tube expansion portion, wherein the first and second peripheral wall portions have different sectional shapes and are fitted together in a partial contact state including predetermined contact and non-contact portions. According to this configuration, the heat transfer tubes can be fixed to a side wall portion of the case and the connecting tube body can be connected to the heat transfer tubes easily and appropriately.

Abstract: 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.

Abstract: Provided is a heat exchanger which includes a plurality of meandering heat transfer pipes that includes first and second heat transfer pipes, as the plurality of heat transfer pipes, which are adjacent to each other in a predetermined y direction and are misaligned with each other in a z direction such that a plurality of straight pipe parts are in a non-overlapping state in the y direction, in which a first recessed part recessed in the y direction is provided in each curved pipe part of the first heat transfer pipe, and a part of each curved pipe part of the second heat transfer pipe is fitted into the first recessed part.

Abstract: A metal bend pipe having a bend portion bent in a semi-circular arc shape is provided, in which an identification part that enables one of the two end portions of the bend portion to be identified as the bending-start side or the bending-end side is provided, and the identification part is integrally formed as a protruding and/or recessed three-dimensional region. Thus, it is possible to easily and reliably identify which of the two end portions of the bend portion is the bending-start side or the bending-end side.

Abstract: A manufacturing method for a pipe structure includes a pipe bending step for implementing for a plurality of times a bending process of bending a part of a straight pipe by wrapping the part around a peripheral surface of a rolling block to form a plurality of bend portions in intermediate locations along a longitudinal direction of the pipe. When a final bending process is implemented during the pipe bending step, a position of a rear end portion of the pipe is determined, and relative positions of the pipe and the rolling block in a predetermined y direction are controlled on the basis of the position of the rear end portion so that after the bending process, a y-direction position of the rear end portion is aligned with a y-direction position of the front end portion.

Abstract: A round metal pipe 1 including a bend portion 10 is configured such that on an axial direction cross-section of the bend portion 10, an outer half portion 11b of a peripheral wall portion 11 of the bend portion 10 has an outwardly projecting, non-circular arc shape in which a central portion in a y direction, which is orthogonal to a bend radius direction x of the bend portion 10, forms an outermost peripheral portion 13, and a distance Lb from respective intermediate portions 15 between the outermost peripheral portion 13 and a pair of proximal end portions 14 of the outer half portion 11b to a pipe center O is shorter than a distance La from the outermost peripheral portion 13 to the pipe center O. Thus, advantages such as suppressing reductions in the sectional area and minimum inside width of the bend portion 10 and reducing flow path resistance can be obtained, and the round metal pipe 1 can be manufactured easily and appropriately.

Abstract: 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.

Abstract: A burner case and a burner device provided with the burner case are disclosed. A cover for closing an opening of a case body of the burner case is attached to the case body by a first caulking portion and a second caulking portion. A first caulking direction and a second caulking direction intersect with each other, the first caulking direction is a direction in which a first attachment piece and a first facing portion, those constituting the first caulking portion, face each other and are caulked, the second caulking direction is a direction in which a second attachment piece and a second facing portion, those constituting the second caulking portion, face each other and are caulked. Thus, the case body and the cover are not required to be screwed or the number of the screws is reduced, and leakage of gas from the burner case to outside is prevented.

Abstract: The burner case has a first member having a caulking portion and a second member having a facing portion facing the caulking portion and an extending portion for caulking, the extending portion extending from the facing portion, the caulking portion being held between the facing portion and the extending portion by bending the extending portion. A part of the extending portion in longitudinal direction constitutes a claw portion. Thus, the first member and the second member are not required to be screwed or the number of screws is reduced, thereby improving productivity of the burner case and reducing the production cost of the burner case.

Abstract: A cover member of a gas supply manifold has a bent rising wall portion that is formed by bending a part of the cover member so as to rise in an opposite direction of a main body. The bent rising wall portion is in a form of a loop surrounding the entire circumference of a gas supply flow path and an area around the gas supply flow path. Such configuration increases the rigidity of the cover member and prevents large distortion of the cover member and leakage of gas from the gas supply flow path. As a result, the thickness of the cover member is reduced and the weight and the production cost of the gas supply manifold are also reduced.

Abstract: A gas supply manifold has a nozzle forming member having a plurality of gas injection nozzles, a cover member configured to be overlapped on the nozzle forming member, and a caulking-fastening portion configured to fasten the nozzle forming member and the cover member. The caulking-fastening portion is configured such that a convex portion provided for one of the nozzle forming member and the cover member penetrates a hole provided for the other member, and a tip end portion of the convex portion has an engagement portion, the engagement portion having a larger diameter or a larger width than the hole and being engaged with a peripheral edge portion of the hole. A tip end face of the convex portion has a dent portion formed by pressing the tip end face into a base portion side of the convex portion and an area around the dent portion constitutes the engagement portion. Thus, the nozzle forming member and the cover member are appropriately caulked and fastened.

Abstract: The burner case has a first member having a caulking portion and a second member having a facing portion facing the caulking portion and an extending portion for caulking, the extending portion extending from the facing portion, the caulking portion being held between the facing portion and the extending portion by bending the extending portion. A part of the extending portion in longitudinal direction constitutes a claw portion. Thus, the first member and the second member are not required to be screwed or the number of screws is reduced, thereby improving productivity of the burner case and reducing the production cost of the burner case.

Abstract: A cover member of a gas supply manifold has a bent rising wall portion that is formed by bending a part of the cover member so as to rise in an opposite direction of a main body. The bent rising wall portion is in a form of a loop surrounding the entire circumference of a gas supply flow path and an area around the gas supply flow path. Such configuration increases the rigidity of the cover member and prevents large distortion of the cover member and leakage of gas from the gas supply flow path. As a result, the thickness of the cover member is reduced and the weight and the production cost of the gas supply manifold are also reduced.

Abstract: A burner case and a burner device provided with the burner case are disclosed. A cover for closing an opening of a case body of the burner case is attached to the case body by a first caulking portion and a second caulking portion. A first caulking direction and a second caulking direction intersect with each other, the first caulking direction is a direction in which a first attachment piece and a first facing portion, those constituting the first caulking portion, face each other and are caulked, the second caulking direction is a direction in which a second attachment piece and a second facing portion, those constituting the second caulking portion, face each other and are caulked. Thus, the case body and the cover are not required to be screwed or the number of the screws is reduced, and leakage of gas from the burner case to outside is prevented.

Abstract: A gas supply manifold has a nozzle forming member having a plurality of gas injection nozzles, a cover member configured to be overlapped on the nozzle forming member, and a caulking-fastening portion configured to fasten the nozzle forming member and the cover member. The caulking-fastening portion is configured such that a convex portion provided for one of the nozzle forming member and the cover member penetrates a hole provided for the other member, and a tip end portion of the convex portion has an engagement portion, the engagement portion having a larger diameter or a larger width than the hole and being engaged with a peripheral edge portion of the hole. A tip end face of the convex portion has a dent portion formed by pressing the tip end face into a base portion side of the convex portion and an area around the dent portion constitutes the engagement portion. Thus, the nozzle forming member and the cover member are appropriately caulked and fastened.