Patent ID: 11874071
Assignee: ALFA LAVAL CORPORATE AB
Field: Thermal processes and apparatus (Mechanical engineering)
Classification: CPC F  B  C | IPC B  C  F

Claim 7:
8. A plate heat exchanger for evaporation, the plate heat exchanger comprising:
first heat exchanger plates and second heat exchanger plates, which form first plate interspaces for a first fluid to be evaporated and second plate interspaces for a second fluid;
each of the first heat exchanger plates and each of the second heat exchanger plates extending in parallel with an extension plane and comprising:
a heat exchanger area extending in parallel with the extension plane of the heat exchanger plate,
an edge area extending around the heat exchanger area, and
a number of portholes extending through the heat exchanger area;

each of the first heat exchanger plates comprising a peripheral rim surrounding a first porthole of said number of portholes and extending transversely to the extension plane from a root end to a top end with a rim height H perpendicular to the extension plane;
each of the first heat exchanger plates comprising at least one restriction hole extending through the peripheral rim and possessing a hole height h perpendicular to the extension plane, the relation h/H being at the most 30%,
the first heat exchanger plates and the second heat exchanger plates being joined to each other via joints of braze material between the first and second heat exchanger plates and arranged in such a way that the peripheral rims define an inlet channel extending through the plate heat exchanger;
the at least one restriction hole forming a fluid passage for the first fluid from the inlet channel to the first plate interspaces to throttle the first fluid entering the first plate interspaces;
the at least one restriction hole being premade before the first heat exchanger plates and the second heat exchanger plates are assembled and joined to each other via the joints to form the plate heat exchanger; and
each of the first heat exchanger plates possessing a thickness, the peripheral rim forming a transition portion to the heat exchanger area, and the transition portion being concavely curved with a radius of curvature equal to or less than 3 times the thickness so that the braze material is attracted toward the transition portion due to capillary forces.