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 13:
14. A method of making a plate heat exchanger configured for evaporation, comprising first heat exchanger plates and second heat exchanger plates, wherein each of the first and second heat exchanger plates has a number of portholes and wherein a first porthole of said number of portholes of the first heat exchanger plates is surrounded by a peripheral rim, the method comprising:
bending the peripheral rim to extend transversely to an extension plane of the first heat exchanger plate from a root end to a top end with a rim height H perpendicular to the extension plane;
making at least one restriction hole through the peripheral rim before or after the bending of the peripheral rim;
arranging the first and second heat exchanger plates side-by-side with braze material therebetween to permit formation of a first plate interspace for a first fluid to be evaporated and a second plate interspace for a second fluid, the arranging the first and second heat exchanger plates side-by-side with braze material therebetween occurring after the making of the at least one restriction hole and after the bending of the peripheral rim; and
heating the first heat exchanger plates, the second heat exchanger plates and the braze material to join the side-by-side heat exchanger plates to each other via joints of braze material between the first and second heat exchanger plates, with the peripheral rims together defining an inlet channel extending through the plate heat exchanger, the at least one restriction hole, which has a hole height h perpendicular to the extension plane, forming a fluid passage for the first fluid from the inlet channel to the first plate interspaces, the relation h/H is at the most 30%, and each of the first heat exchanger plates possessing a thickness, with 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.