1. A product distribution device, comprising: a frame supported at least partially by wheels to move over the surface； a hopper for containing the product to be distributed； a meter adapted to control the rate of output of the product from the hopper； a product distribution system receiving the product from the meter； scales for selective weighing of a part of the product from the hopper； and a calibration valve for selectively directing the product exiting the meter to one of the distribution system and weights. 2. The device according to claim 1, in which the balance includes a receiving tank mounted on the frame using one or more load cells configured to measure the weight of the product in the receiving tank. The device according to claim 1, further comprising a controller and an actuator for controlling the position of the calibration valve. The device according to claim 3, in which the controller in the working position is connected to the balance for receiving input from them and to the drive motor of the meter to control the meter. The device according to claim 4, further comprising a speed sensor for determining the speed of the device. The device according to claim 1, further comprising means for returning the product from the balance to the hopper. The device according to claim 1, further comprising a return line from the balance to the hopper and a fan adapted to blow air through the balance to move the product from the balance along the return line to the hopper. A method for calibrating a meter in a product distribution device, the device having a frame supported at least partially by wheels to move along the surface1. Устройство распределения продукта, содержащее:раму, поддерживаемую, по меньшей мере, частично колесами для перемещения по поверхности；бункер для содержания распределяемого продукта；измеритель, приспособленный для регулирования скорости выдачи продукта из бункера；систему распределения продукта, принимающую продукт от измерителя；весы для в
