A double pipe includes an outer pipe, an inner pipe, a fin member and a sealing part. The outer pipe has a plurality of outer crimping parts projecting to an inner diameter side and aligned in at least one of a lengthwise direction and a circumference direction. The inner pipe is arranged on an interior of the outer pipe with a flow path gap being defined between the outer pipe and the inner pipe. The inner pipe has a plurality of inner crimping parts aligned in the at least one of the lengthwise direction and the circumference direction and overlapping the outer crimping parts. The fin member is arranged on the interior of the inner pipe and held by the inner crimping parts. The sealing part seals between the outer pipe and the inner pipe.

An apparatus for forming and sealing a duct member for use in an air handling system. At least one work station accommodates a work piece, which is generally a cylindrical tube.

A method of forming a heat exchanger tube, particularly suited for condensing applications, contemplates cold-rolling a metallic strip to emboss a hydrophobic surface texture, to thereby form an embossed surface on the metallic strip. The method includes roll forming the metallic strip to a tubular shape, with the embossed surface on the exterior of the tubular shape, and welding the edges of the roll-formed strip to form a heat exchanger tube. Cold-rolling to emboss a hydrophobic surface texture exhibiting a contact angle of at least about 75 is contemplated, with processing including heat-treatment to minimize degradation of the hydrophobic surface texture, and roll-forming to avoid deformation of the hydrophobic surface texture,

A method of forming a heat exchanger tube, particularly suited for condensing applications, contemplates cold-rolling a metallic strip to emboss a hydrophobic surface texture, to thereby form an embossed surface on the metallic strip. The method includes roll forming the metallic strip to a tubular shape, with the embossed surface on the exterior of the tubular shape, and welding the edges of the roll-formed strip to form a heat exchanger tube. Cold-rolling to emboss a hydrophobic surface texture exhibiting a contact angle of at least about 75 is contemplated, with processing including heat-treatment to minimize degradation of the hydrophobic surface texture, and roll-forming to avoid deformation of the hydrophobic surface texture,

The production method for producing a rifled tube, which includes a plurality of first helical ribs on its inner surface, includes: a steps of: preparing a steel tube; and producing a rifled tube by performing cold drawing on a steel tube by using a plug which includes a plurality of second helical ribs, the plug satisfying Formulae and:
0.08 <W(AB)N/(2A)<0.26(1)
0.83<S(AB)N/(2M)<2.0(2)
where, W is a width of a groove bottom surface of the helical groove; A is a maximum diameter of the plug; B is a minimum diameter of the plug; N is a number of the second helical ribs; S is the width of the groove bottom surface; and M is a pitch of adjacent second helical ribs.

The production method for producing a rifled tube, which includes a plurality of first helical ribs on its inner surface, includes: a steps of: preparing a steel tube; and producing a rifled tube by performing cold drawing on a steel tube by using a plug which includes a plurality of second helical ribs, the plug satisfying Formulae and:
0.08 <W(AB)N/(2A)<0.26(1)
0.83<S(AB)N/(2M)<2.0(2)
where, W is a width of a groove bottom surface of the helical groove; A is a maximum diameter of the plug; B is a minimum diameter of the plug; N is a number of the second helical ribs; S is the width of the groove bottom surface; and M is a pitch of adjacent second helical ribs.

An evaporator suitable for a thermal dissipation module. The thermal dissipation module includes a tube or pipe and fluid. The evaporator includes a housing, a first heat dissipation structure and a second heat dissipation structure disposed in a sealed chamber of the housing. The chamber is configured to communicate with the pipe, and the fluid is configured to flow in the pipe and the chamber. The first heat dissipation structure and a second heat dissipation structure provide a plurality of fluid flow passages through which the fluid flows and evaporates. A manufacturing method of the evaporator is also disclosed.

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.

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.

A heat exchanger includes a tube having a length and an outside boundary. The tube is configured to convey fluid therethrough to facilitate heat transfer, and the outside boundary of the tube having a bottom wall portion, a top wall portion opposing the bottom wall portion, and two side wall portions between the bottom wall portion and the top wall portion, in which a segment of the length of the tube has a plurality of dimples selectively placed outside of the bottom wall portion.