Performance Index
Ratio of the actual electrical response of a pH electrode per pH unit to the theoretical response predicted by physical laws defines the efficiency of the measurement sensor. This value, called slope percentage, is calculated during the calibration cycle of the meter using two different buffer solutions. It indicates the overall health of electrodes in laboratory and industrial instruments.
Testing Significance
Accurate calibration of the dyebath controller requires a high slope percentage to ensure that pH adjustments are precise. When the slope falls below ninety-five percent, the sensor responds slowly and may fail to detect rapid pH changes during alkali addition. This sluggishness can lead to over dosing and fabric damage.
Dyehouse Consequence
Uneven dye fixation on cellulose fabric occurs if the pH meter is calibrated with an electrode of poor slope. If the actual slope is lower than the recorded value, the meter under-corrects the readings, leading to incorrect calculations of active alkali. This difference causes shade variation along the length of the processed roll.
Maintenance Boundary
Cleaning the glass membrane with mild acid can sometimes restore the slope percentage to acceptable levels. If the value remains below ninety percent after cleaning, the sensor must be replaced to maintain production quality.
