Abstract: The invention relates to an injector dosing mechanism (1) for an apparatus, in particular a sandblasting mechanism (30), for dosed addition to a liquid, such as anticorrosive agent, to a stream produced by the apparatus, having a container (2) for taking up the liquid and a connecting pipe (31) leading to the pipe (32) carrying the stream, the apparatus being operated via a switch-on mechanism (33). To permit a constant dosage of liquid without readjustment in a constant or varying air stream or even despite interruption of the air stream, a control valve (17, 18) controlled via a switching mechanism is disposed in the connecting pipe (31), the switching [means] mechanism being coupled with the switch-on [means] mechanism (33) of the apparatus and switching the control valve (17, 18) in accordance with the pulses from the switch-on [means] mechanism.