Conductivity Measurement in Fruit & Vegetable Lye Peeling

Many fruits and vegetables are prepared for peeling and canning by exposure to lye or caustic soda (NaOH). To ensure consistent peeling, the concentration of caustic in the treatment bath must be maintained at an effective strength. During the process, a significant amount of caustic is carried out by the product, so the bath must be continually replenished to maintain an adequate volume and concentration of caustic solution. This may involve the addition of water, based on level control, as well as additional caustic, based on the conductivity measurement. Due to its resistance to fouling, toroidal conductivity is the best measurement technique in this application. For relatively clean processes, the Rosemount™ 228 Toroidal Conductivity Sensor is the best solution. For applications with the potential for heavy coating, the Rosemount 226 Toroidal Conductivity Sensor is a better solution.