A hydraulic system comprises a valve distributor comprising one or more sections connectable to respective uses, a supply apparatus comprising a pump and a supply channel, a discharge channel connected to a low-pressure tank, a use signal channel coming from the section of the valve distributor and further comprises a hydraulic regulating device connected via said channels which includes a 2-position 3-way proportional valve configured so as to provide operative fluid at a conditioned pressure, different with respect to the pressure that is characteristic of the operative condition of use, to the supply apparatus and at least one proportional pressure reducing valve.

A consumer control device, with which an external consumer device can be supplied with compressed air in a controlled manner, contains a compressed air maintenance unit, equipped with a proportional pressure regulating valve that can be electrically actuated, which is connectable via an outlet channel with the consumer device to be actuated. In the outlet channel an electrically controllable shut-off valve and an outlet pressure sensor are connected, both of which communicate with an internal electronic control unit, which is also supplied with information on the air flow in the outlet channel. The consumer control device can be operated according to a similarly proposed method, in that the consumer device in a normal operating phase is supplied with compressed air by the shut-off valve that is in the release position, which is regulated by a proportional pressure regulating valve adopting working mode at a working pressure value.

A hydraulic system comprises a valve distributor comprising one or more sections connectable to respective uses, a supply apparatus comprising a pump and a supply channel, a discharge channel connected to a low-pressure tank, a use signal channel coming from the section of the valve distributor and further comprises a hydraulic regulating device connected via said channels which includes a 2-position 3-way proportional valve configured so as to provide operative fluid at a conditioned pressure, different with respect to the pressure that is characteristic of the operative condition of use, to the supply apparatus and at least one proportional pressure reducing valve.

In a method of controlling a main control valve of an excavator, when speeds of a boom cylinder and an arm cylinder is increased by handling a boom joystick and an arm joystick, a second arm control spool between a first hydraulic pump and the arm cylinder may be closed. A first boom control spool between the first hydraulic pump and the boom cylinder may be opened to supply a first flux generated from the first hydraulic pump to the boom cylinder. A second boom control spool between a second hydraulic pump and the boom cylinder may be closed. A first arm control spool between the second hydraulic pump and the arm cylinder may be opened to supply a second flux generated from the second hydraulic pump to the arm cylinder.

A consumer control device, with which an external consumer device can be supplied with compressed air in a controlled manner, contains a compressed air maintenance unit, equipped with a proportional pressure regulating valve that can be electrically actuated, which is connectable via an outlet channel with the consumer device to be actuated. In the outlet channel an electrically controllable shut-off valve and an outlet pressure sensor are connected, both of which communicate with an internal electronic control unit, which is also supplied with information on the air flow in the outlet channel. The consumer control device can be operated according to a similarly proposed method, in that the consumer device in a normal operating phase is supplied with compressed air by the shut-off valve that is in the release position, which is regulated by a proportional pressure regulating valve adopting working mode at a working pressure value.

In a method of controlling a main control valve of an excavator, when speeds of a boom cylinder and an arm cylinder is increased by handling a boom joystick and an arm joystick, a second arm control spool between a first hydraulic pump and the arm cylinder may be closed. A first boom control spool between the first hydraulic pump and the boom cylinder may be opened to supply a first flux generated from the first hydraulic pump to the boom cylinder. A second boom control spool between a second hydraulic pump and the boom cylinder may be closed. A first arm control spool between the second hydraulic pump and the arm cylinder may be opened to supply a second flux generated from the second hydraulic pump to the arm cylinder.