Patent ID: 8728279

Claim:
A system for measuring a component in a kraft pulping, liquor that has a pH of at least 8.5 that comprises: a sensor device having a first electrode and a second electrode that are neither shielded nor covered with a baffle and that are configured to be positioned in the kraft pulping liquor wherein the sensor device measures the amount of NaOH, Na 2 S, and/or Na 2 CO 3 in the kraft pulping liquor wherein the sensor device has an aperture opposite the first electrode and the second electrode; a controller operative to supply a varying current to the first electrode wherein the second electrode receives a current from the first electrode and wherein the sensor device generates signals corresponding to the amount of NaOH, Na 2 S, and/or Na 2 CO 3 in the kraft pulping liquor; a reservoir containing an aqueous mixture of polymer scaling inhibitors; and a pump that continuously delivers an effective amount of the aqueous mixture of polymer scaling inhibitors through the aperture into the liquor in the vicinity of the first electrode and the second electrode with the proviso that the aqueous mixture of polymer scaling inhibitors is not applied directly to the first electrode or the second electrode, characterized in that the presence of the polymer scale inhibitors does not interfere with measurement by the sensor device and scale deposition in the form of salts that are present in the liquor onto the first electrode and second electrode is inhibited as current flows from the first electrode to the second electrode which permits continuous operation of the sensor device for more than a month without cleaning.