| 摘要 |
A valve assembly is provided to control a flow of liquid through a drain conduit from a sink in an aircraft. When the aircraft is in an inactive condition on the ground, a fluid motor presses a main valve member lightly against a main valve seat. At this time, liquid in the drain conduit can leak past the main valve member. However, at this time, the main valve member is effective to block a reverse flow of odors through the drain line into the cabin of the aircraft. When the aircraft is operating in the air above the ground, the motor presses the main valve member against the main valve seat with sufficient force to seal the drain conduit and prevent the leakage of fluid past the main valve seat. When a predetermined amount of liquid has accumulated in the drain conduit upstream from the main valve seat, a motor control assembly effects operation of the motor to move the main valve member away from the main valve seat to allow the liquid to flow through the drain conduit past the main valve seat.
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