A diaphragm pump is provided for the pressurized delivery of dusts in a dust feeding device. The diaphragm pump includes a storage hopper which is subjected to inert gas at ambient pressure and which serves for the storage of the dust. A sluicing vessel is provided which is connected via an inlet in the upper region, via a shut-off fitting and via a dust supply line to the dust store of the storage hopper, and is connected via an outlet in the lower region and via a shut-off fitting to a high-pressure device. A diaphragm is mounted in the sluicing vessel. An expansion line is provided, one end of which is connected via a filter element to the sluicing vessel and into which a shut-off fitting is incorporated. The diaphragm pump includes charging line which is connected via a filter element and via a shut-off fitting to the sluicing vessel.