Patent ID: 6889707

Claim:
An ON/OFF valve ( 1 , 1 ′, 1 ″) comprising: an outer body ( 3 ) defining a fluid flow cavity ( 2 ) divided by an intermediate surface ( 8 , 21 ) into a first and a second chamber ( 2 a , 2 b ) communicating with each other via an opening section ( 6 , 28 ) in the intermediate surface ( 8 , 21 ); and a flexible shutter ( 7 ) having, on the side facing said first chamber ( 2 a ), a membrane portion ( 17 ) cooperating elastically, by virtue of a fluid pressure, with said intermediate surface ( 8 , 21 ) and with said opening section ( 6 , 28 ) to separate said first and said second chamber ( 2 a , 2 b ) hermetically; characterized by comprising fluid leakage generating means ( 20 , 27 ) located between said membrane portion ( 17 ) of said shutter ( 7 ) and said opening section ( 6 , 28 ), and which are active when the pressure in said first chamber ( 2 a ) exceeds the pressure in said second chamber ( 2 b ) by an amount equal to or less than a threshold value (P) other than zero, said fluid leakage generating means including a number of grooves ( 20 ) formed in said intermediate surface ( 8 ) that are equally spaced about a central axis (A) of said intermediate surface ( 8 ) and extend radially with respect to said axis (A), said grooves ( 20 ) communicating with said opening section ( 6 ), and said threshold value (P) being a function of the geometry of said grooves ( 20 ).