Application of turbulent pulsating flows to the bacterial removal during a cleaning in place procedure. Part 2: Effects on cleaning efficiency

Abstract

Pulsating turbulent flows effects on cleaning in place procedure of straight pipes were investigated for various pulsations parameters (frequency and amplitude) and mean velocities of the flow. Pulsations generation was made with a new system which allows high amplitude of pulsations. Experiments showed the contribution of the different pulsation parameters, in the removal of adhered bacterial spores, in addition to the effect of the mean velocity of the flow. A high level of the cleaning rate is observed despite the reduction of the magnitude of the mean velocity. This result can be explained by the effect of the two pulsations parameters (amplitude and frequency) which ensure a high wall shear rate. The study of the cleaning kinetics has shown the increase of the removal constant rate of spores using pulsed flow in comparison with the use of a steady turbulent flow.

Minimising the environmental footprint of industrial-scaled cleaning processes by optimisation of a novel clean-in-place system protocol

“…Some previous works suggest advantages of applying different CIP procedures such as pulsing cleaning chemicals (Christian and Fryer, 2006) or pulsed flows (Blel et al, 2009).…”

Generation of Coarse Bubbles and Flow Instability Control by Means of a Bubble Generator

“…Pulsating and oscillatory flows provide for rapidly changing shear stresses on the membrane surface, which contribute to the prevention of fouling and thus assist the filtration process. At the same time, transient flows exert lift and drag forces on the particles and facilitate the migration of particles from the membrane surface to the bulk flow . For example, the filtration performance of yeast cell harvesting was greatly improved by using oscillatory flow mixing in both tubular and flat‐sheet membrane systems .…”

Pulsatile Jet Cleaning of Filter Cloths Contaminated with Yeast Cells

“…A potential approach is the utilization of pulsatile jets. It had already been shown that a change from continuous to pulsed cleaning results in higher cleaning rates in pipes or surfaces from particles or other types of fouling . The filtration performance of membranes or filter cloths, in particular, is enhanced by using pulsatile flows, which are in some cases even more effective than cross‐flows , , .…”