| 摘要 |
<p>There is described an ON/OFF valve (1, 1', 1') having an outer body (3) defining a fluid flow cavity (2) divided by an intermediate surface (8, 21) into a first and a second chamber (2a, 2b) communicating with each other via an opening section (6, 28) in the intermediate surface (8, 21); a flexible shutter (7) having, on the side facing the first chamber (2a), a membrane portion (17) co-operating elastically, by virtue of a fluid pressure, with the intermediate surface (8, 21) and with the opening section (6, 28) to separate the first and second chamber (2a, 2b) hermetically; and fluid leakage generating means (20, 27) located between the membrane portion (17) of the shutter (7) and the opening section (6, 28), and which are active when the pressure in the first chamber (2a) exceeds the pressure in the second chamber (2b) by an amount equal to or less than a threshold value (P) other than zero.</p> |
