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.

Abstract: In a plant for cooling heated goods, for instance cast iron, the goods is transported in a predetermined direction through one or several cooling sections (1,2,3). Through the tunnels a closed piping system (4) transports a fluid in a direction which is opposite to the transportation direction of the goods. The piping system also comprises at least one heat exchanger in which at least part of the heat from the goods is transferred to the fluid under the intermediary of a separate cooling medium which is brought in direct contact with the goods. A considerable part of the heat being emitted from the goods can thereby be transferred to the fluid and the heat energy thus taken care of can either be converted to electric energy or be directly used for heating purposes.