Scott and Tabibi phase into the other by feeding it into the vicinity of the mixing/dispersing element. In this way, the phase being added is quickly dispersed into the continuous phase. Although it is widely accepted that the higher the shear rate produced by the mixer the smaller the droplets and, hence, the more stable the emulsion, there is a major prob-lem that must be avoided if good results are to be obtained with high-speed mixing equipment. Every effort should be made to avoid incorporating air into the mix. Air forms a third phase that could ruin emulsion stability in a number of ways. Air usu-ally reduces the viscosity. The addition steps should be organized such that the impel-ler of the mixture is always submerged deeply enough to avoid surface turbulence or splashing. The arrangement of the mixer angle and/or baffles should avoid vortexing. Another alternative is to perform all of the emulsion-making steps in a vacuum-pro-cessing vessel. An additional method is to premix the components at low speeds and shear rates and then subsequently execute the high-shear portion of the process with in-line equipment in the absence of air. In short, aeration should be avoided. Sometimes the direct approach is not the most effective one. When one phase is first added to another, the small amount of liquid being added forms the internal phase. If more of this liquid is added there comes a point where the continuous phase loses its ability to hold all of the internal phase and the emulsion inverts to the opposite type, e.g., from O/W to W/O. Since it has been found that this practice (phase inversion) can yield small droplet sizes, this method is widely used in batch processing. To ex-ecute this maneuver, one needs to begin mixing with only a small amount of liquid in a batch that will later increase to usually more than four times the starting volume. Therefore, the mixer has to extend well to the bottom of the vessel. One way to avoid this small volume of starting liquid is by using an in-line mixer in a recirculation loop attached to the main mixing vessel as illustrated in Fig. 5. The initial phase is recirculated through the in-line high mixer and the phase to be inverted is then carefully metered directly into the recirculation line. This avoids Fig. 5 In-line mixer in recirculation loop to kettle.

DOI link for Scott and Tabibi phase into the other by feeding it into the vicinity of the mixing/dispersing element. In this way, the phase being added is quickly dispersed into the continuous phase. Although it is widely accepted that the higher the shear rate produced by the mixer the smaller the droplets and, hence, the more stable the emulsion, there is a major prob-lem that must be avoided if good results are to be obtained with high-speed mixing equipment. Every effort should be made to avoid incorporating air into the mix. Air forms a third phase that could ruin emulsion stability in a number of ways. Air usu-ally reduces the viscosity. The addition steps should be organized such that the impel-ler of the mixture is always submerged deeply enough to avoid surface turbulence or splashing. The arrangement of the mixer angle and/or baffles should avoid vortexing. Another alternative is to perform all of the emulsion-making steps in a vacuum-pro-cessing vessel. An additional method is to premix the components at low speeds and shear rates and then subsequently execute the high-shear portion of the process with in-line equipment in the absence of air. In short, aeration should be avoided. Sometimes the direct approach is not the most effective one. When one phase is first added to another, the small amount of liquid being added forms the internal phase. If more of this liquid is added there comes a point where the continuous phase loses its ability to hold all of the internal phase and the emulsion inverts to the opposite type, e.g., from O/W to W/O. Since it has been found that this practice (phase inversion) can yield small droplet sizes, this method is widely used in batch processing. To ex-ecute this maneuver, one needs to begin mixing with only a small amount of liquid in a batch that will later increase to usually more than four times the starting volume. Therefore, the mixer has to extend well to the bottom of the vessel. One way to avoid this small volume of starting liquid is by using an in-line mixer in a recirculation loop attached to the main mixing vessel as illustrated in Fig. 5. The initial phase is recirculated through the in-line high mixer and the phase to be inverted is then carefully metered directly into the recirculation line. This avoids Fig. 5 In-line mixer in recirculation loop to kettle.

Scott and Tabibi phase into the other by feeding it into the vicinity of the mixing/dispersing element. In this way, the phase being added is quickly dispersed into the continuous phase. Although it is widely accepted that the higher the shear rate produced by the mixer the smaller the droplets and, hence, the more stable the emulsion, there is a major prob-lem that must be avoided if good results are to be obtained with high-speed mixing equipment. Every effort should be made to avoid incorporating air into the mix. Air forms a third phase that could ruin emulsion stability in a number of ways. Air usu-ally reduces the viscosity. The addition steps should be organized such that the impel-ler of the mixture is always submerged deeply enough to avoid surface turbulence or splashing. The arrangement of the mixer angle and/or baffles should avoid vortexing. Another alternative is to perform all of the emulsion-making steps in a vacuum-pro-cessing vessel. An additional method is to premix the components at low speeds and shear rates and then subsequently execute the high-shear portion of the process with in-line equipment in the absence of air. In short, aeration should be avoided. Sometimes the direct approach is not the most effective one. When one phase is first added to another, the small amount of liquid being added forms the internal phase. If more of this liquid is added there comes a point where the continuous phase loses its ability to hold all of the internal phase and the emulsion inverts to the opposite type, e.g., from O/W to W/O. Since it has been found that this practice (phase inversion) can yield small droplet sizes, this method is widely used in batch processing. To ex-ecute this maneuver, one needs to begin mixing with only a small amount of liquid in a batch that will later increase to usually more than four times the starting volume. Therefore, the mixer has to extend well to the bottom of the vessel. One way to avoid this small volume of starting liquid is by using an in-line mixer in a recirculation loop attached to the main mixing vessel as illustrated in Fig. 5. The initial phase is recirculated through the in-line high mixer and the phase to be inverted is then carefully metered directly into the recirculation line. This avoids Fig. 5 In-line mixer in recirculation loop to kettle.