The PIZETA screw dosing batches raw materials in a continuous and constant way through a rotary valve to the relevant machine through a pneumatic conveyor. It has a tubular body with a spiral auger inside, which can be designed with a variable gauge to meet the client’s particular requirements. The screw feeder rotation is driven by a motor reducer controlled by an inverter to guarantee the variation in capacity required by the client. The screw feeder also has a safety system to prevent blockages in the unloading outlet. This prevents damage to the machine in the case of a malfunction.