Definition
A laboratory dispersion homogenizer is a sample preparation equipment used to evenly disperse, refine, and stably distribute solid particles or droplets in a liquid medium. It realizes the mixing, emulsification, homogenization and dispersion of materials through mechanical force, and is widely used in the preparation process of laboratory samples in food, chemical industry, materials, environmental science and other fields.
Principle
Laboratory dispersion homogenizers usually work on the principle of high-speed shearing. Its core component is a rotor-stator structure, which rotates at high speed driven by a motor to draw the sample from the bottom to the working head. In the narrow gap between the rotor and the stator, the sample is subjected to strong mechanical shear force, high-frequency vibration and hole effect, so that the particles or droplets are quickly broken and dispersed to form a uniform and stable mixture. The process can describe the shear rate of the material using the following relationships:
γ = (π × D × N) / h
where γ represents the shear rate, D is the rotor diameter, N is the rotor speed, and h is the clearance distance between the rotor and the stator. Higher shear rates often help achieve a more refined dispersion effect.
Measurement and evaluation methods
The evaluation of dispersion homogenization is usually based on the particle size distribution and system stability of the dispersed phase. Common measurement methods include laser particle size analyzer to determine particle size and distribution width, microscope to observe dispersion morphology, and static layering experiment to evaluate stability. In standardization operations, quantitative comparisons can be made with reference to relevant industry standards (such as dispersion fineness test standards in the field of coatings and cosmetics).
Influencing factors
The dispersion homogenization effect is affected by multiple factors. The equipment parameters include rotor speed, head geometry, processing time and temperature control. Sample properties such as material viscosity, solids content, particle hardness, and interface properties also significantly affect the results. Operating conditions such as dosing sequence, vessel shape and immersion depth are also taken into account. Optimizing these parameters helps to obtain a dispersion system that meets the requirements.
Applications
Laboratory dispersion homogenizers are suitable for many scientific research and quality inspection scenarios that require fine dispersion. In the food industry, it is used to prepare homogeneous emulsions for sauces, dairy products, etc.; In the chemical field, it is used for sample preparation of nanomaterials, coatings, and inks; For the homogenization of suspended solids in soil or water in environmental analysis; Used in cosmetics research and development for laboratory simulation production of cream products. The aim is to provide a representative homogeneous sample for subsequent testing.
Selection considerations
Choosing the right laboratory dispersion homogenizer requires comprehensive consideration of experimental needs. The sample throughput determines the equipment specification and working head size. The viscosity and hardness of the material affect the required power and speed range; Samples sensitive to temperature rise need to pay attention to cooling or temperature control functions; In addition, material compatibility, ease of cleaning, operational safety and compliance with relevant standards are also important considerations. It is recommended to compare different technical parameters according to actual application scenarios.