Additive dosing appts. with two sources

摘要

An additive dosing appts. for a (pref. concrete) mixer has a first measuring device (2) for determining feed material parameters which determine the additive amount to be supplied; a line (9) which is connected to a first additive source and which has a first dosing device (3a) with a valve; a controller (4) connected, at its input side, to the output of the first measuring device (2) and, at its output side, to the valve of the first dosing device (3a) for controlling this valve; and a line (8) which is connected to a second additive source having a variable additive amount and which has a second dosing device (3b) with a valve.The novelty is that (a) a second measuring device (6) is provided for detecting the additive amount present in the second source, the device output being connected to an input of the controller (4); (b) the valve of the second dosing device (3b) is connected to an output of the controller (4); and (c) the controller (4) is designed so that additive supply occurs through the second dosing device (3b) and, when the additive amount in the second source is insufficient, the difference is made up by additive supply through the first dosing device (3a).