Patent ID: 8443742

Claim:
An agricultural machine comprising: a seed metering device to meter seeds for the distribution to the ground across which the agricultural machine moves; a pressure actuating device; an air line; a return line; and a dump line, wherein the seed metering device includes a wall that is arranged to rotate, the seed metering device is arranged to communicate with the pressure actuating appliance to provide a wall pressure difference between a seed reception side of the wall and an opposite side of the wall that is opposite the seed reception side, wherein the pressure is higher on the seed reception side than on the opposite side, wherein the wall is provided with a plurality of through retention openings for the reception on the seed reception side of the wall, by the wall pressure difference, of seeds at the retention openings for subsequent transportation, by the rotation of the wall, through a wall transportation distance and releasing of the seeds, wherein the pressure actuating appliance comprises a pneumatic device connected to the air line, wherein the pneumatic device provides a main air current through the air line toward the seed reception side of the wall, wherein the return line is connected between the opposite side of the wall that is opposite the seed reception side and the pneumatic device, and wherein a part of the main air current is arranged to be brought back to an inlet side of the pneumatic device through the return line, while a part of the main air current is arranged to be directed down into the ground through the dump line.