Evaluation of a rinsing-based cleaning process for pipes

Pipes of various designs were constructed. Pipes were filled with a model solution resembling a dermal solution product. After the removal of the model solution, pipes were rinsed several times with ethanol and rinsing solutions of each step analyzed by gas chromatography. The results gave the information about the dependency between the configuration of the pipe and the efficiency of the cleaning operation. From concentrations measured in the reactor, expected concentrations in rinsing solutions from pipes were predicted. The obtained results confirm that the amount of residues per surface area increases when a pipe includes bends and valves. In terms of extra contamination, each bend was equal to 25 cm, while each valve was equal to 100 cm of pipe length when pipes of 1.8 cm in diameter were used. It was proven that the contributions of individual valves and bends in the pipe are additive in the calculation. The validity of the proposed model was confirmed by experimental data.