A computer-based ph measurement and control system for fermentation processes

The measurement and control of pH is essential in most fermentation processes. The highly nonlinear response of pH to the addition of acid or base makes pH control by conventional means very difficult. This paper presents a description of the hardware and software of a computer-based pH measurement and control system. The system is applicable to any fermentation process requiringin situ pH measurement and control and is capable of controlling the pH within ±0.1 U with a very short response time. It has a proportional metering device capable of adding the required amount of acid (or alkaline) solution with high accuracy, thereby preventing overshooting.