Patent ID: 8453671

Claim:
An apparatus for controlling an internal pressure of a hermetically sealed chamber at a prescribed pressure level, comprising: an inlet passage connected to an external environment through an inlet aseptic filter, for supplying air to said hermetically sealed chamber; an outlet passage connected to the external environment through an outlet aseptic filter, for discharging a gas from said hermetically sealed chamber; an inlet valve for selectively opening and closing said inlet passage; an outlet valve for selectively opening and closing said outlet passage; a controller for controlling said inlet valve and said outlet valve to control an internal pressure of said hermetically sealed chamber; and pressure relaxing means connected to said outlet passage between said hermetically sealed chamber and said outlet valve, for relaxing abrupt pressure changes in said hermetically sealed chamber, wherein said outlet passage includes an outlet duct, and said pressure relaxing means comprises an elastic member disposed in an internal space in said outlet duct which is separate from the hermetically sealed chamber with the outlet aspetic filter interposed therebetween.