Patent ID: 6595222
Filing Date: 2003-07-22
Classification: C23G

Abstract:
A chemical cleaning apparatus for cleaning metal strip including a chemical cleaning section and at least one rinse section, means for feeding a coil of metal strip through the cleaning and rinse section(s), spray nozzles mounted on transverse headers in the chemical cleaning section adapted to spray chemical cleaning solution onto top and bottom faces of the metal strip, mechanical means for moving at least some of the transverse headers closer together or farther apart, thereby varying a dwell time of the cleaning solution on the metal strip, and a programmable logic controller adapted to develop a dwell time signal and move the headers closer together or farther apart in response to the dwell time signal, wherein the dwell time signal is developed by providing the programmable logic controller with a set point value for each coil of metal strip which defines for standard conditions of chemical concentration and temperature the time the strip should be exposed to the chemical spray, measuring the temperature and concentration of the chemical solution in the cleaning section, feeding the temperature and the concentration measurement to the programmable logic controller and obtaining said dwell time signal based on said set point value and temperature and concentration measurement.