In the case of suction apparatuses for disposing of flammable collected material, such as magnesium or aluminium chips, damage to or destruction of the filter device as well as the turbine of the suction unit in the event of a fire breaking out in the collecting receptacle of said suction apparatus is to be avoided and the fire extinguished. A protective device which can be triggered thermally and interrupts the suction draught in the event of appropriate heat development in the collecting receptacle serves this purpose.
