Cooling section comprising power cooling and laminar cooling
A cooling section for flat rolling stock has a working region, through which the flat rolling stock is guided. The working region can be supplied with a liquid coolant by means of a number of spray beams. The liquid coolant is fed from a reservoir for the liquid coolant to the spray beams by means of a pump and a supply system. Valves are arranged upstream of the spray beams in the supply system. Opening positions of the valves are set by a control unit of the cooling section according to a respective sub-flow that is to be applied to the flat rolling stock by means of each spray beam. Also, the delivery rate of the pump and/or a line pressure generated by the pump in the supply system are set by the control unit according to the total flow that is to be applied to the flat rolling stock by means of all the spray beams.
1. A method for cooling a rolling stock with a liquid coolant, comprising:
guiding the rolling stock through a working region comprised of a plurality of spray beams oriented and configured to spray the liquid coolant on the rolling stock being guided through the working region;
pumping the liquid coolant to the spray beams from a reservoir via a pump and a supply line system to the spray beams;
using a control unit to set opening positions (si) of valves which are arranged upstream of the spray beams and within the supply line system according to a respective partial flow (fi) through the valves to be applied to the rolling stock by means of each respective spray beam; and
using the control unit to reduce a delivery power of the pump and/or reduce a line pressure (p) generated by the pump in the supply line system upstream of the valves according to a total flow (F) of the liquid coolant to be applied to the rolling stock by spray from all of the spray beams together by summing all of the partial flows (fi) through the valves arranged upstream of each of the respective spray beams,
wherein the control unit further sets the opening positions of the valves arranged upstream of the spray beams to be relatively open wide and reduces the delivery power of the pump and/or the line pressure generated by the pump to avoid cavitation of the liquid coolant in each valve at the set open position of each valve.
2. The method as claimed in claim 1 , wherein the rolling stock is a flat rolling stock having flat surfaces on which the spray beams spray coolant.