Method and apparatus for monitoring the partial density of metal and acid in pickling baths

Claim 1

A method for measuring and monitoring the partial densities of metal and acid in a bath of pickling liquid, comprising: irradiating the pickling liquid by gamma radiations (x,y) having two different energy levels to obtain two gamma radiation counting rates (I x , I y ); and deriving representations of the partial densities (r 2 , r 3 ) of two components of the liquid from the measured counting rates and known substance-specific and/or system-specific parameters and calibration values in a control and evaluation unit, wherein said step of deriving is performed in accordance with the following equations: ##EQU6## η x2 and η x3 are the mass extinction coefficients of respective components with respect to radiation x; η y2 and η y3 are the mass extinction coefficients of respective components with respect to radiation y; η x1 and η y1 are the mass extinction coefficients of a reference liquid with respect to radiations x and y, respectively; k o , k 1 , k 2 and k 3 are empirically determined constants; T ist is the actual operating temperature of the pickling liquid bath; T m is the mean temperature of the bath; γ is the coefficient of expansion of the bath; L x and L y are the measurement length for radiations x and y, respectively; I ox and I oy are the unattenuated intensities of radiations x and y, respectively.

Claim 2

A method for measuring and monitoring the partial densities of metal and acid in a bath of pickling liquid, comprising: irradiating the pickling liquid by gamma radiations (x,y) having two different energy levels to obtain two gamma radiation counting rates (I x , I y ); and deriving representations of the partial densities (r 2 , r 3 ) of two components of the liquid from the measured counting rates and known substance-specific and/or system-specific parameters and calibration values in a control and evaluation unit, wherein said step of deriving is performed in accordance with the following equations: ##EQU6## η x2 and η x3 are the mass extinction coefficients of respective components with respect to radiation x; η y2 and η y3 are the mass extinction coefficients of respective components with respect to radiation y; η x1 and η y1 are the mass extinction coefficients of a reference liquid with respect to radiations x and y, respectively; k o , k 1 , k 2 and k 3 are empirically determined constants; T ist is the actual operating temperature of the pickling liquid bath; T m is the mean temperature of the bath; γ is the coefficient of expansion of the bath; L x and L y are the measurement length for radiations x and y, respectively; I ox and I oy are the unattenuated intensities of radiations x and y, respectively.

Claim 8

An apparatus for measuring and monitoring partial densities of metal and acid in a bath of pickling liquid by irradiating the pickling liquid by gamma radiations (x, y) having two different energy levels to obtain two gamma radiation counting rates (I x , I y ) an deriving representations of the partial densities (r 2 , r 3 ) of two components of the liquid from the measured counting rates and known substance-specific and/or system-specific parameters and calibration values, said calibration values being obtained by irradiating with gamma radiation substances other than said pickling liquid to be monitored, said system-specific parameters being determined by counting rates (I ox , I py ) of unattenuated gamma radiations (x, y) and associated irradiated measurement lengths (L x , L y ), said apparatus comprising: a conduit connected to define a flow path for one of the pickling liquid and each of the subtances other than the pickling liquid, said conduit having two measurement locations traversing said flow path and having a first section at which a first one of said measurement locations is located and which defines a portion of said flow path which is coaxial with the given radiation path; two gamma emitters each disposed for directing gamma radiation through said flow path at a respective one of said measurement locations; and a control and evaluating unit for deriving said representations of said partial densities.

Claim 9

An apparatus for measuring and monitoring partial densities of metal and acid in a bath of pickling liquid by irradiating the pickling liquid by gamma radiations (x, y) having two different energy levels to obtain two gamma radiation counting rates (I x , I y ) an deriving representations of the partial densities (r 2 , r 3 ) of two components of the liquid from the measured counting rates and known substance-specific and/or system-specific parameters and calibration values, said calibration values being obtained by irradiating with gamma radiation substances other than said pickling liquid to be monitored, said system-specific parameters being determined by counting rates (I ox , I py ) of unattenuated gamma radiations (x, y) and associated irradiated measurement lengths (L x , L y ), said apparatus comprising: a conduit connected to define a flow path for one of the pickling liquid and each of the subtances other than the pickling liquid, said conduit having two measurement locations traversing said flow path and having a first section at which a first one of said measurement locations is located and which defines a portion of said flow path which is coaxial with the given radiation path; two gamma emitters each disposed for directing gamma radiation through said flow path at a respective one of said measurement locations; and a control and evaluating unit for deriving said representations of said partial densities.