Abstract: Heat exchange plates are stacked, with a pressing force applied to the plates so as to maintain parallelism of them and prevent deformation of them during a diffusion bonding process. The stacking condition is maintained and adjacent plates come into contact with each other at projections and peripheral edges. Space surrounding the contact portions of the plates is put in a vacuum or low pressure state in which only an inner gas atmosphere exists. The plates are kept at a temperature at which the diffusion bonding occurs by a predetermined period of time to diffusion-bond portions of the plates, which are only brought into contact with each other and have not been bonded together.

Abstract: A heat exchange plate has a main heat transfer section and a fluid guiding portion having first and second sub-patterns of irregularity, respectively. The second pattern of irregularity includes projections and recesses. At least a part of straight or curved lines along which the projections and recesses are aligned has an end located in a predetermined position of an edge of the plate, which forms at least one of inlet and outlet portions and another end that does not coincide with the end located on a boundary between the fluid guiding portion and the main heat transfer section.

Abstract: A heat exchange unit is composed of rectangular heat transfer panels with terraced flat portions, combined in parallel and integrally with each other to form first and second spaces. Outer and inner reinforcement members having respective serrations are welded to the panels so that the serrations are inserted into gaps between the heat transfer panels. The outer and inner reinforcement members are made of the same material as the heat transfer panels and have a larger thickness than the heat transfer panel, so as to bear high heat input given during the welding. The heat input caused by welding can be increased to enable portions of the heat transfer panels to be melted rapidly.

Abstract: A heat exchange unit includes metallic heat transfer members combined with each other. Each heat transfer member has a heat transfer face having opposite surfaces with which first and second heat exchange fluids come into contact, respectively. Welded-together flat portions of the heat transfer members are inserted into a fitting hole of an end plate. The fitting hole substantially coincides with an end shape of the combined heat transfer members and is sized to slidably receive welded-together flat portions such that the end plate and the received, welded-together flat portions contact each other. After insertion, the heat transfer members are welded to the end plate along the fitting hole so that, at the welded region, the heat transfer members and the end plate form an integral construction.

Abstract: A seam welding apparatus enables, even when metallic sheets are arranged in a line in a short distance, the welding electrodes to come into contact only with the metallic sheet to be welded, so as to provide a reliable welding of the metallic sheets to form connected portions having high strength. The roller electrode 20, which has on its outer peripheral portion the conical electrode surface 21, is supported by the central axis inclined relative to the surface of the metallic sheet 50 to be welded, and there is provided the stationary electrode 30 in which the portion including the flat electrode surface 31 has the smaller thickness. The electrode surface 21 of the roller electrode 20 is brought into contact with the surface of one of the metallic sheets 50 to be welded, while bringing the electrode surface 31 of the stationary electrode 30 into contact with the surface of the other metallic sheet 50.

Abstract: A heat exchange plate having a pattern of irregularity is combined with the other plates to constitute a heat exchanger. The plate has main and intermediate protrusions. The main protrusions have a quadrangular pyramid shape with a top, first and second pairs of side surfaces. The first and second pairs of side surfaces face each other in the first and second directions. The main protrusions are aligned in these directions so that these pairs of surfaces of the main protrusion face the corresponding surfaces of adjacent protrusions. The intermediate protrusion is placed between adjacent main protrusions and has opposite foot portions and a head ridge placed between them. The foot portion is placed in a lowermost position at which ridgelines of the adjacent two main protrusions intersect. The head ridge is placed in a level higher than the foot portions, but lower than the top of the main protrusion.

Abstract: A press-forming apparatus comprises a pair of press-forming units detachably secured to movable and stationary units facing each other, respectively. A metallic material is subjected to a press-forming through the press-forming units and then discharged therefrom as a heat transfer member for a heat exchanger. Each of the press-forming units comprises (i) a main forming section for forming on the material a heat transfer face with a corrugated portion, (ii) a pair of first subsidiary forming sections disposed on upstream and downstream sides of the main forming section so as to be adjacent thereto in the feeding direction of the material and (iii) a forming section-support base member detachably supporting the main forming section and the first subsidiary forming sections.

Abstract: A method for manufacturing a heat transfer member comprises the step of subjecting material to be worked, which is made of a metallic thin sheet, to a press forming utilizing upper and lower molds of a press-forming devices to form the material to be worked into a shape having prescribed irregularities, thereby preparing a heat transfer member for a heat exchanger. An elongated material is used as the material to be worked. A press-forming device is provided with molds each having a length shorter than the elongated material to be worked.

Abstract: A method for manufacturing a heat transfer member comprises the steps of: subjecting elongated materials to be worked, which are made of metallic thin sheets, to a continuous press forming utilizing a plurality of press-forming devices to form heat transfer faces each having a prescribed shape, while transferring the materials in a prescribed feeding direction, which is in parallel with a longitudinal direction of the materials; and welding two materials, which have been subjected to the press forming, of the elongated materials together utilizing a welding device to form a heat transfer member having substantially a tubular shape.