| 摘要 |
<p>PCT No. PCT/SE95/00768 Sec. 371 Date Dec. 23, 1996 Sec. 102(e) Date Dec. 23, 1996 PCT Filed Jun. 22, 1995 PCT Pub. No. WO96/01963 PCT Pub. Date Jan. 25, 1996The invention relates to a valve system for a space (1) which is under vacuum in relation to its surroundings (3), which valve system comprises a valve unit (7) which is intended to be arranged in association with a wall (2) which delimits the said space and has a wall opening (4) through the said wall, which valve unit comprises a valve (8) which is normally shut and closes the said wall opening but is arranged to be opened and allow air from the surroundings into the said space if the vacuum, i.e. the difference between the surrounding pressure and the pressure in the space, should exceed a previously defined value, which valve comprises a valve housing (12) which can be connected to the said wall (2) in association with the wall opening and which has at least one inlet opening (17) for air, a passage (6) for the air between the said, at least one, inlet opening and the said space (1), a valve seat (15) and a valve body (13) with a sealing surface (21) which is normally pressed against the valve seat by an external force with counteraction by the vacuum in order to keep the passage closed when the vacuum does not exceed the defined value but to permit the passage to be opened by the force developed by the vacuum on the valve body overcoming the external force when the vacuum exceeds the said value. According to the invention, the external force is obtained from a pneumatic power source (34).</p> |
