Method for controlling a quantity flow of particles and control arrangement for carrying out the method

摘要

In a method and a device for controlling a quantity flow of particles (2, 2a) from a source (1) to a sink (3), the source (1) is equipped with a conveying device (4) for the discharge of particles at an adjustable quantity per unit time. From the sink (3) a material which is formed with the aid of the particles is drawn off at a predetermined quantity per unit time. In order to make possible a disturbance-free control process over a long time, the particles (2, 2a) are individualised on the way to the sink (3) and are counted by at least one sensor (21, 22). The sequence of counting pulses is fed to a counter (25) and compared in this with a corresponding sequence of desired value pulses. The comparison signal, formed from counting pulses and desired value pulses, is used as a control signal for matching the quantity of particles discharged per unit time from the source (1) to the desired value, taking into account its sign. Method and device are used in particular for the controlled charging of a melting crucible (13) with doped particles during the drawing of a crystal (16) in accordance with the Czochralski method.