The valve plate (1) with free micro-balls allows a fluid (2) to flow from an upstream volume (3) to a downstream volume (4) and not in the reverse direction, and comprises a circulation plate (5) crossed through by a circulation orifice (6) terminated by a micro-ball seat (7), a permeable guide plate (9) parallel to said plate (5) being crossed through by a guide cylindrical orifice (10) which houses a micro-ball (8) which rests on said seat (7) so as to close said orifice (6) or rests on a permeable micro-ball stop abutment (11), a spacer (12) being interposed between said plate (9) and said plate (5), a discharge passageway (13) crossing through said plate (9) to allow the fluid (2) to flow when the micro-ball (8) does not rest on said seat (7).