Abstract: A collecting bag for collecting dusts having an air permeable bag body made of a cloth and provided at its one end with a connection opening for connection to a passage of the dust laden air and at its other end with a discharge opening through which the dust content of the bag is taken out. A pair of opposing plate members are jointed to the opposing peripheral edges of the discharge opening of the bag body so as to cooperate with each other in opening and closing the discharge opening. One of the plate members may be provided with a hook which engages a suitable member fixed to the bag in the closed state of the discharge opening.

Abstract: A collecting apparatus having a nozzle through which air is released to form a jet flow, a restriction provided at a position spaced from the nozzle in the direction of the jet flow and a vacuum sleeve defining a large vacuum space between the nozzle and the restriction. A collecting tube is connected to the vacuum sleeve to open to the vacuum space. A high vacuum is established in the vacuum space so that large dusts are sucked through the collecting tube and collected in a collecting bag attached to the restriction or scattered through the restriction.