Definition
A positive-displacement pump that uses flat vanes sliding in slots within an off-center rotor inside a circular housing. As the rotor turns, the vanes are pushed outward against the housing wall by centrifugal force or springs, forming sealed pockets that grow on the inlet side to draw fluid in and shrink on the outlet side to push fluid out under pressure.
Plain English
A pump with a spinning rotor that has small sliding blades around its edge. As the rotor turns, the blades trap pockets of fluid and squeeze them through the pump, moving fluid steadily and at controlled pressure.
Context Anchor
Seen in aircraft systems that need steady air or fluid movement, such as vacuum systems, hydraulic systems, and some fuel or oil system discussions.
Derivation
From Latin vannus, a winnowing fan. The thin sliding blades inside the pump look and act like small fan blades sweeping fluid around the housing.
Why Pilots Care
Engine-driven vane-type vacuum pumps spin the gyros in attitude and heading instruments. If the pump fails, those instruments slowly spool down, which is why pilots monitor the suction gauge and know which instruments are vacuum-driven.
Analogy
Picture a revolving door with flat panels that keep making small spaces as it turns. A vane-type pump works in a similar basic way: the moving panels form pockets that carry air or fluid through the pump.
Intuition Check
Do not think of the vanes as fan blades that simply stir air around. In a vane-type pump, the vanes trap small pockets and move them through the pump in a controlled flow.
Example Sentence 1
The aircraft's gyroscopic instruments are powered by an engine-driven vane-type pump that maintains steady suction.
Example Sentence 2
During preflight the mechanic inspects the vane-type pump for worn vanes that could reduce output pressure.