Abstract: In a dust extraction system for woodworking machinery, the dust is collected by a hood over each machine and is carried by an air flow produced by a blower through a branch conduit to a manifold which is common to a number of branch conduits. The manifold is made sufficiently large that the air flow velocity in the manifold is too low to carry the dust along the manifold, and therefore the dust collects at the bottom of the manifold, from which it is removed at intervals by a conveyor, which carries the dust to a central hopper. A control system keeps the subatmospheric pressure in the manifold substantially constant, so that the number of machines served by the system can be changed without affecting the system performance.