A pneumatic pump device coupled to a container for flowable material includes a jet pump with at least one intake duct extending away from the container and leading into the jet pump and an air supply duct extending away from the container and to which pressure can be applied or which leads to an outer surface of the pneumatic pump device. The intake duct and air supply duct have essentially the same orientation in the region of the container and are advantageously inclined relative to the vertical by not more than 40°. A metering system includes a container and such a pneumatic pump device coupled thereto and the use of the pneumatic pump device or metering system in a sanding system of a rail vehicle.