METHOD FOR MODIFYING SURFACES OF PLATES OF A BRAZED PLATE HEAT EXCHANGER Russian patent published in 2021 - IPC C23C24/08 C30B23/02 B82B3/00 

FIELD: heat exchange.

SUBSTANCE: invention relates to a method for modifying surfaces plates of a brazed plate heat exchanger (BPHE). Plates and a carbon-containing target are placed in a vacuum chamber. The chamber is pumped out to the required vacuum level of 10^-5-10^-7 Torr and laser treatment of the target is carried out, followed by condensation of a modified layer containing diamond phases on the surface of the plate. The modified layer is applied by evaporation of the carbon-containing target by pulsed laser radiation with a wavelength of 190-310 nm, a pulse duration of 1-100 ns with a repetition frequency of 10-100 Hz and an energy density of 1-10 J/cm² on the target surface. The content of diamond phases in the modified layer is from 5 to 15%, and the thickness of the modified layer is from 30 to 300 nm. A stencil is placed above the treated surface to protect plate sections from applying the modified layer to sections intended for the subsequent formation of a junction of BPHE plates with each other.

EFFECT: technical result consists in increasing the service life, reducing the load on the hydraulic system and increasing the efficiency of heat exchange, and it is achieved by hardening the surface and reducing hydrodynamic losses when the content of diamond phases in the modified layer is from 5 to 15%.

2 cl, 1 dwg