Vacuum Cycling Nucleation (VCN)
for internal cleaning of parts:
VCN works inside tight offsets. On the initial vacuum
air is removed from the internals of the part.
On the initial pressure cycle fluid is forced into the
void spaces within the part.
On the subsequent vacuum cycles vapor bubbles grow inside
the part and force fluid from the internals of the part.
Reactant chemicals, soluble material, particles and surfactant
micelles are purged from the part during this cycle.
On the subsequent pressure cycles fluid reenters the part’s
internals bringing fresh treatment chemicals.
Cycling continues until the part is fully processed.
The picture depicts the process.
The video shows some applications.
The video shows vapor bubble formation within an internal
porous matrix. The porous part behaves like a sponge during
the pulsing VCN process. Fluid is expelled from the part during
the vacuum cycle as when squeezing a sponge and then the pores
are filled with fresh fluid during the pressure cycle as when
a sponge is submerged in a fluid.
Nucleation selectively forms in the holes,
trenches, and under particles - where convective heat transfer
is restricted, thus allowing nucleation to progress unabated.