CONTROL SYSTEM FOR HYDRAULIC UNITS OF ROLLING MILL FOR CORE MOULD MATERIALS Russian patent published in 2016 - IPC B21B13/10 

FIELD: pipe.

SUBSTANCE: invention relates to pipe rolling. Stand (100) of rolling mill comprises at least three rolls, cassette-holder of rolls, hydraulic units and control system. When extracting cassette-holder of rolls (3) from lateral side in stand travel length of hydraulic units, required for removal of pistons of hydraulic units from trajectory of cassette-holder (3) of rolls during extraction of cassette-holder (3) from rolling mill, can reach values from 150 to 400 mm, value can negatively affect response time of system of controlling position of said hydraulic units (4′′).

EFFECT: to increase responsiveness of control system, possibility to quickly and accurately respond to sudden pressure changes in control circuits, invention uses four-way servo valves with two or more stages, in which hydraulic connection is made with possibility of connection of pressure hole P with main chamber and outlet T with annular chamber, and vice versa, pressure hole P - with annular chamber, and outlet hole T - with main chamber.

3 cl, 7 dwg