Key Factors Influencing the Emulsification Effect of Vacuum Emulsifiers

What factors affect the emulsification performance of vacuum emulsifiers? The primary considerations are outlined below:

High-Shear Mixing Emulsifiers

Capable of producing emulsions and suspensions with relatively large but narrowly distributed particle sizes. Featuring high shear rates, they ensure the stability of mixed liquids. Different working heads (stator + rotor) are tailored to specific process requirements and fluid dynamics.

High-Shear Dispersion Emulsifiers

Primarily designed for processing large volumes of emulsions and generating ultra-fine suspensions. Equipped with three working heads, they deliver extremely narrow particle size distribution and smaller droplets/particles, resulting in superior stability of the mixed liquid. The easily replaceable dispersion heads accommodate diverse applications.

High-Speed Shear Homogenizing Emulsifiers

Boasting shear rates exceeding 10,000 rpm (note: corrected from "100.00 rpm" for technical accuracy) and rotor tip speeds up to 40 m/s, these emulsifiers leverage shear-induced turbulence combined with specially engineered motors to achieve nano-scale particle sizes. They offer enhanced shear force and narrower particle size distribution.

Laboratory-Scale Dispersion Emulsifiers

Tailored for R&D purposes, these units mirror the configuration of large-scale industrial in-line production models—including matching working head types and linear speeds. Process parameters validated during pilot trials require no re-adjustment for industrial scaling, minimizing risks associated with equipment upgrade.

In-Line High-Shear Dispersion Emulsifiers

Ideal for applications demanding ultra-high precision grinding, capable of achieving nano-scale particle sizes with enhanced shear force and narrow size distribution. Particularly suited for vaccines, cell disruption, colloidal solutions, inks, printing coatings, pigment mixing, etc.

Emulsification Temperature

Temperature significantly impacts emulsification outcomes, though no strict limitations apply. For liquid oil-water systems, emulsification can be achieved at room temperature via stirring. Typically, the emulsification temperature is determined by the melting point of high-melting components in either phase, as well as emulsifier type and oil-water solubility. Critically, the two phases should be maintained at similar temperatures—especially when emulsifying oil phases containing waxes or fats with melting points above 70℃. Adding low-temperature aqueous phases to such systems may cause wax/fat crystallization, resulting in lumpy or uneven emulsions. Generally, a temperature range of 75℃–85℃ is recommended for both phases; higher temperatures may be required if the oil phase contains high-melting waxes. Additionally, if viscosity increases excessively during emulsification (impeding stirring), moderate temperature elevation can help. For emulsifiers with a specific phase inversion temperature, emulsification is best performed near this temperature. Temperature also affects droplet size: for example, when using fatty acid soap anionic emulsifiers via the nascent soap method, emulsification at 80℃ yields droplets of ~1.8–2.0μm, whereas emulsification at 60℃ results in larger droplets (~6μm). Non-ionic emulsifiers exhibit weaker sensitivity to temperature in terms of droplet size.

Emulsification Time

Emulsification time directly influences emulsion quality and is determined by oil-water volume ratio, phase viscosities, target emulsion viscosity, emulsifier type and dosage, and emulsification temperature. The core objective is to ensure thorough emulsification, which is closely linked to equipment efficiency. Optimal emulsification time can be established through experience and experimentation—for instance, homogenizers operating at 3,000 rpm typically require only 3–10 minutes.

Stirring Speed

Stirring speed is a critical factor in emulsification. Moderate speeds ensure sufficient oil-water mixing: excessively low speeds fail to achieve uniform blending, while excessively high speeds introduce air, creating an unstable three-phase system. Air entrainment must be avoided during stirring.

Additional Influencing Factors

Other key considerations include: working head type, shear rate, tooth profile, material residence time in the dispersion chamber, emulsification/dispersion duration, and circulation cycles. To maximize the performance of vacuum emulsifiers, these factors should be carefully optimized during operation.