Feeding of a pressurised device with variable grain sizing solid

A system for conveying solid from a first tank to a second tank comprising:

• an introduction device which can be connected to the first tank;
• a first conveying device connected to the introduction device, comprising a first endless screw including a shaft fitted with a projecting helical winding in a first winding direction and having a first constant pitch, and a sleeve in which the first screw is located and is configured to rotate, the sleeve comprising at least one counter screw including a projecting helical winding on an inner surface of the sleeve and in a second winding direction opposite to the first winding direction and having a second pitch at least equal to five times the first pitch;
• a second conveying device comprising a second endless screw having an axis perpendicular to the shaft of the first endless screw of the first device, and which comprises a helical winding of spirals at least one of which is able to abrade compressed matter, and a sleeve in which the second screw is located and is able to rotate;
• a discharge device which are put into relation with the second device;
• and
• the second tank which is pressurized and connected to the discharge device.