A method for controlling a rotation speed of a first and a second shaft (AI, A2) of an industrial shredder (T) for materials to be sorted and/or disposed of, and intended to be shredded between blades of said first and said second shaft (AI, A2), the shredder (T) further comprising:
- pressure sensor means (P1, P2) operatively connected to said first and said second shaft (AI, A2) to detect a pressure (Pp1, Pp2) caused on the first and the second shaft in relation to a resistance of a material to be shredded, at periodic time intervals in subsequent work periods;
- a first and a second hydraulic motor (M1, M4;
- M2, M3) operatively connected respectively with said first and said second shaft (AI, A2) to impart a determined rotation speed thereto;
- a first and a second hydraulic pump (P01, P02) respectively having an initial (Por1_II, Por2_I) and final (Por1_F, Por2_F) flow rate value in each work period and a predefined maximum flow rate value (Por1_max, Por2_max), each one of said first and a second hydraulic pump being operatively connected respectively to said first and said second hydraulic motor (M1, M4;
- M2, M3), said at least one first and one said second pump (P01, P02) further being operatively connected to drive means (MM1, MM2) and a respective first and second solenoid valve (E1, E2) which regulates a flow rate thereof, the first and the second solenoid valve being proportional to the rotation speed of said first and said second shaft (AI, A2);
- and
- a logic control unit (UL) operatively connected with to said pressure sensors means (P1, P2) and said first and said second solenoid valve (E1, E2), said logic control unit (UL) being configured to compare a pressure value (Pp1, Pp2) detected by said pressure sensor means (P1, P2) with a predetermined threshold pressure value (P threshold) set or which can be set in said logic control unit (UL) and lower than a pressure value for blocking a rotation of said first and said second shaft (AI, A2), the logic control unit (UL) further being configured to act on said first and said second solenoid valve (E1, E2) so as to regulate the flow rate value of the respective first and second pump (P01, P02);
- the method sequentially and iteratively comprising, in subsequent work periods, the steps of:
- detecting, by said pressure sensor means (P1, P2), the pressure value (Pp1, Pp2) of the respective shaft (AI, A2) of said first and said second shaft (AI, A2) in a predetermined time instant within a work period;
- comparing, by said logic control unit (UL), the pressure value (Pp1, Pp2) detected by said pressure sensor means (P1, P2) with the threshold pressure value (P threshold);
- and
- setting, by said logic control unit (UL), a final flow rate value (Por1_F, Por2_F) of said first and said second pump (PO1, P02);
- wherein if said pressure value (Pp1, Pp2) detected by said sensor means (P1, P2) of at least one of said first and said second shaft (A1, A2) is greater than or equal to said threshold pressure value (P threshold), said setting step occurs by reducing the initial flow rate value (Por1_I, Por2_I) of at least one of said first and said second pump (PO1, P02) by at least one first or one second predetermined value (R1;
- R2) set or which can be set in the logic control unit (UL) to obtain a final flow rate value (Por1_F, Por2_F) lower than that of the initial flow rate (Por1 . . . I, Por2_I), so as to reduce the rotation speed of the respective shaft between said first and said second shaft (AI, A2) and facilitate the shredding of the material to be sorted and/or disposed of, that is interposed between the first and the second shaft (AI, A2);
- or
- wherein if said pressure value (Pp1, Pp2) detected by said sensor means (P1, P2) of both said first and second shaft (AI, A2) is lower than said threshold pressure value (P+threshold), said setting step occurs by regulating the final flow rate value (Por1_F, Por2_F) of said first and second pump (PO1, P02) equal to the respective maximum value (Por1_max, Por2_max).