Control system and method for switching pivot stands in a tandem rolling mill
AssigneeAEG Automation Systems Corporation
InventorsHarold B. Bolkey, Thomas J. Morrow
Life of this patent
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Abstract
In a master speed regulator system for a multi-stand rolling mill, a control system and method for switching a pivot stand via a bumpless transfer back and forth from the second stand to the last stand depending on the phases of the mill and while the mill is operating. A microprocessor is used for recalculating the master speed reference B1, the integral values for the master speed reference integral controller, and the outputs for the tension/automatic gauge integral controllers for the new pivot state based on conditions of the previous pivot state.
Claims14
In a continuous rolling mill for rolling strip material, said mill having a threading operation, a full run operation, and a tailing operating, comprising:
- at least two roll stands operating at a predetermined speed, one of said stands adjacent an entry end and a second of said stands adjacent an exit end for said mill, and
- control means for controlling said mill, including first means for selecting and causing said one stand adjacent said entry end to act as a pivot stand during said threading operation and said tailing operation of said mill, second means for transferring control of said mill and selecting and causing said second stand adjacent said exit end to act as said pivot stand during said full run operation of said mill, and third means for causing said speed of said second stand to be the same speed as said speed of said one stand when said second means of said control means is in operation and said speed of said one stand to be the same as said speed of said second stand when said first means of said control means is in operation.
In a continuous rolling mill for rolling strip material and having at least three stands being driven at a speed and one of said stands being adjacent an entry end and a second being adjacent an exit end for said mill, comprising:
- control means for controlling said mill with said stand adjacent said entry end acting as a pivot stand during a threading or a tailing operation of said mill and transferring while said mill is in operation to controlling said mill with said stand adjacent said exit end acting as a pivot stand during a full run operation of said mill,
- said control mean comprising;
- master speed regulator means for obtaining a master speed reference value as an output for regulating said speed of each of said stands, and having an integral controller for establishing an instantaneous speed for one of said stands acting as said pivot stand and for constantly updating said master speed reference value,
- said master speed regulator means including means for recalculating said master speed reference value for said pivot stand adjacent said exit end based on said master speed reference value of said pivot stand adjacent said entry end, and for recalculating said master speed reference value for said pivot stand adjacent said entry end based on said master speed reference value of said pivot stand adjacent said exit end,
- means for redirecting said output of said master speed regulator means from said pivot stand adjacent said entry end to said pivot stand adjacent said exit end and from said pivot stand adjacent said exit end to said pivot stand adjacent said entry end,
- speed regulator means having means for producing an output and for receiving an input and associated with each of said stands and with said master speed regulator means for regulating said speed of said each of said stands, and tension and automatic gauge control means having means for producing an output and associated with each of said speed regulator means of said each of said stands and having an integral controller, and including means for recalculating said output of said tension and automatic gauge control means for said full run operation of said mill based on said input to said speed regulator means of said each of said stands during said threading or tailing operation for an upstream stand and a downstream stand relative to a said tension and automatic gauge control means.
A method for operating a continuous rolling mill in a first mode of operation and a second mode of operation, wherein said first mode of operation is a threading operation or a tailing operation and said second mode of operation is a full run operation for said mill, said mill having at least three stand with a stand adjacent an entry end and a stand adjacent an exit end, said stands being driven at a speed, the steps comprising:
- during said threading and tailing operation of said mill, selecting said stand adjacent said entry end as a pivot stand, and
- during said full run operation of said mill, selecting said stand adjacent said exit end as said pivot stand.
Dependencies are inferred from the claim text.