Pneumatic transport system of granular material and control method of such system

A control method of a pneumatic transport system of granular material, comprising the following operating steps:

• a) preparing:
• at least one loading device of the granular material for a processing machine, said device being provided with a collection tank of the granular material;
• at least one conveying duct of granular material which fluidically connects the collection tank to at least one storage container of granular material;
• and
• means for generating flow of granular material inside the conveying duct from the container to the tank of the loading device;
• b) loading the tank with said material generating a flow of granular material from the container to the tank;
• c) detecting by a sensor vibrations induced on the loading device by the granular material which is being loaded inside the loading device, and generating time signals;
• d) estimating progressively over time a filled level of the collection tank correlating to said time signals of the vibrations of the mass of granular material loaded in the tank, by modal analysis of said signals, or the volume of the collection tank progressively filled by said granular material, on the basis of frequency and/or amplitude variations of said signals;
• and
• e) controlling the means for generating flow to activate or suspend the flow of material towards the loading device depending on the estimated filled level of the tank to optimize filling time of the tank.