Abstract: A fan impeller comprises a back plate, a front plate and a plurality of blades fixedly attached between the front plate and the back plate. Two bars are welded to the back of each blade and are bolted to the front and back plates. Each blade is a channel section member having a base and two sides, the base being normal to the planes of the front and back plates of the impeller, one side lying along the front plate and the other side lying along the back plate. The sides extend from the base in the direction of rotation of the impeller in use so that the inside of each channel section is presented to the airstream as the impeller rotates. The inside working surface of each blade may be hardened to a minimum hardness of Rockwell C55.

Abstract: A vacuum operated refuse collecting vehicle includes an air-tight container mounted on the chassis of the vehicle and having an outlet communicating with means for generating a vacuum within the container. A suction conduit is provided for each side of the vehicle, each suction conduit extending at one end into the interior of the container and being provided at the other end with a nozzle which may be disposed at a short distance from the ground. Brrush means are provided. Means are mouned at said one end of each conduit which are operable from outside the container, for separately closing off said one end of each suction conduit to prevent refuse entering said one end of the conduit when it is closed. Said one ends of said suction conduits communicate with the container in positions one on each side of a central longitudinal plane of the container and adjacent one end of the container.