Abstract: A plate heat exchanger includes a stack of a plurality of plates each having an inlet and an outlet for a fluid. Each adjacent two of the plates are bonded to each other at regions thereof where top parts of the wavy portion provided in a lower one of the plates and bottom parts of the wavy portion provided in an upper one of the plates overlap each other when seen in the stacking direction. Particularly, a top part included in the top parts of the wavy portion of the lower plate and being adjacent to each of the inlet and the outlet has a planar shape.

Abstract: A plate heat exchanger includes a stack of a plurality of plates each having an inlet and an outlet for a fluid. Each adjacent two of the plates are bonded to each other at regions thereof where top parts of the wavy portion provided in a lower one of the plates and bottom parts of the wavy portion provided in an upper one of the plates overlap each other when seen in the stacking direction. Particularly, a top part included in the top parts of the wavy portion of the lower plate and being adjacent to each of the inlet and the outlet has a planar shape.

Abstract: In a plate heat exchanger, it is aimed to enhance strength, such as the pressure resistance and the internal pressure fatigue resistance, by increasing the joint area of a joint portion joined by brazing in a wave-patterned portion. Before a brazing process of the plate heat exchanger, a plurality of plates are stacked and pressure is applied thereto. By this pressure process, indentations of approximately “0.05 mm to 0.1 mm” are formed at contact points 9 of wave patterns in adjoining lower and upper plates. By brazing the plates after this pressure process, the joint area of the joint portion joined by brazing is increased. The increased joint area enhances the joint strength, and thus the strength of the plate heat exchanger such as the pressure resistance and the internal pressure fatigue resistance can be enhanced.