Why not measure conductivity with an electrodeless system?
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heatstone bridge-type instruments and conventional electrodetype cells have been successfully applied to a great many industrial control problems. However, in solutions containing abrasive or fibrous solids, and very conductive or highly corrosive solutions, the problem of servicing the conductivity cell and maintaining the electrodes in gOQd working condition is severe enough to limit the use of the method. The Type RS4 electrodeless conductivity measuring system, eliminates liquid/electrode contact problems and has extended use of the conductivity method to many new solutions and slurries. These include the following: • Black Liquor • Hydrofluoric Acid • Molten Ammonium Nitrate • 1 0 % Sodium Hydroxide • Slurry of Bauxite and NaOH " 9 8 % Sulfuric Acid • Sea Water • Nitric Acid and Uranyl Nitrate • Sulfuric Acid and
Copper Sulfate • Cement Slurry • Industrial Sewage • Hydrochloric Acid and Aluminum Chloride • Magnesium Bisulfite "Drilling Mud. The RS4 electrodeless conductivity system (U. S. Patent 2,542,057) measures the resistance of a closed loop of solution by the extent to which the loop couples two toroidal transformers. The solution loop is variously formed, sometimes by plastic piping, otherwise by metallic piping provided with a non-conductive liner. One of the toroidal coils is connected to a transmitter which supplies a voltage in the high audio-frequency range. The output of the transmitter must be stable and free from drift in both frequency and amplitude. The second toroidal coil is connected to a receiver which measures the output voltage from this winding. With constant input voltage, the output of this system is proportional to the conductivity of the solution. The
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receiver is a high impedance input, highly degenerated vacuum tube voltmeter. The output from the amplifier is rectified in a conventional bridge-type meter rectifier and displayed directly on a large indicating meter. By placing a small resistor in series with the meter, a millivolt signal is provided for feeding a remote potentiometer recorder when desired. High and low alarm and other control features may be incorporated as desired. Perhaps the Electrodeless System is the answer to your questionable conductivity application. For further information, contact your Beckman sales representative, or write direct.
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