Patent DE-102011075627-A1 (DE)
Title: Secondary cooling device, useful for cooling metal strand in strand guide roller after its exit from mold, comprises cooling circuit with pump, strand guide roller with cooling passages, coolant control valve, and coolant shutoff valve
Inventor: PLOCIENNIK UWE
IPC: B22D11/124
Filed: 2011-05-11
Abstract: The secondary cooling device comprises a cooling circuit (110) with a pump (111) to promote a coolant (150), a strand guide roller with a first cooling passage (112) and a second cooling passage, where the first and second cooling passages are designed as partial sections of the cooling circuit, a coolant control valve located in an inlet of the first cooling passage for controlling the volumetric flow of the coolant by the first cooling passage, and a coolant shutoff valve located in an inlet of the second cooling passage for closing the second cooling passage against the flow of coolant. The secondary cooling device comprises a cooling circuit (110) with a pump (111) to promote a coolant (150), a strand guide roller with a first cooling passage (112) and a second cooling passage, where the first and second cooling passages are designed as partial sections of the cooling circuit, a coolant control valve located in an inlet of the first cooling passage for controlling the volumetric flow of the coolant by the first cooling passage, a coolant shutoff valve located in an inlet of the second cooling passage for closing the second cooling passage against the flow of the coolant, a control device to actuate the coolant control valve and the coolant shutoff valve, where the control device is formed to close the second cooling passage by actuating the coolant shutoff valve against an entry of the coolant if a metal strand (200) is made of a tear-sensitive material, a flushing system having a compressor for blowing out residues of the coolant from the second cooling passage by gas and compressed air after the second cooling passage is closed by the coolant shut off valve against the entry of the coolant, a first temperature measuring unit, a second temperature measuring unit, and a third temperature measuring unit. The flushing system comprises a gas shutoff valve whose outlet opens into the inlet of the second cooling passage between the coolant shutoff valve and the strand guide roller to open or close the second cooling passage against the entry of the gas. The first temperature measuring unit is provided for measuring the surface temperature of the metal strand, which is cooled in the strand guide roller. The control device is adapted to adjust the volume flow of the coolant in the first cooling passage by controlling the coolant control valve in response to the measured surface temperature of the metal strip such that the surface temperature of the metal strip does not fall below a predetermined temperature-strand threshold. The second temperature measuring unit is provided in the inlet of the first cooling passage, and the third temperature measuring unit is provided in the first cooling passage for detecting a change in temperature of the cooling medium. The control device further adjusts the volumetric flow of the coolant by actuating the coolant control valve according to the detected change in temperature in the first cooling passage so that the change in the temperature does not exceed predetermined temperature threshold level. The strand guide roller is designed as a cladding roller or a turret roller. The introduction or removal of the coolant guided in the two cooling passages is carried out by rotary joints mounted at an end face or lateral surfaces of a roller pin of the strand guide roller or by feedthroughs in a roller body of the strand guide roller. The first cooling passage is formed along the longitudinal axis of the strand guide roller. The second cooling passage is formed, at inlet and outlet sides of the strand guide roller, in the form of an annular channel portion concentrically surrounding the first cooling channel. The annular channel portions branch off in the radial direction via a connecting channel extending parallel to outer surface of the strand guide roller. The connecting channel is formed as a portion of the second cooling channel of the strand guide roller, and is present in helical or spiral form. An independent claim is included for a method of operating a secondary cooling device.