The steady flow cell is designed for the stable measurement of contact conductivity sensors, ensuring that the sulfuric acid flowing through the sensor remains stable in real time, avoiding measurement errors due to pressure or flow fluctuations. The equipment is suitable for measuring dry acid concentration, second absorption acid concentration, finished acid concentration and first absorption acid concentration. It is a key auxiliary tool to solve the problem of measurement fluctuation of acid concentration in acid plant. It is compatible with the installation of various brands of conductivity acid concentration meter sensors, and has the characteristics of safety and maintenance free.