High shear homogenizerIt belongs to high-power mechanical equipment. The energy consumption of a high-pressure homogenizer with a flow rate of two tons is 45 kW, while the energy consumption of a colloid mill with the same flow rate is only 7.5 kW. Taking the processing of emulsions as an example, different industries use different surfactants, but one thing is common, that is, the amount of surfactant added to the emulsion depends on the amount of energy obtained during the emulsification process. The greater the energy obtained, the less dosage is added. For example, when processing emulsifiers under a pressure of 40Mpa in a high-pressure homogenizer, the dosage of active agent added is 0.25%. When using other homogenization equipment, such as processing emulsions with a colloid mill, the dosage of additives must be at 2.25% due to the much lower energy obtained from the colloid mill, and the difference between the two is almost an order of magnitude.

Compared to centrifugal dispersing and emulsifying equipment such as colloid mills and high shear mixing emulsifiers, the characteristic of high shear homogenizers is that they have a stronger refining effect. This is because the valve core and seat of the working valve are tightly fitted in the initial position, but a narrow slit is forced out by the liquid during operation; In order to achieve high-speed rotation and not generate excessive heat, there must be a large gap between the stator and rotor of the centrifugal emulsification equipment (compared to the homogenization valve); Meanwhile, since the transmission mechanism of the homogenizer is a positive displacement reciprocating pump, theoretically speaking, the homogenization pressure can be infinitely increased, and the higher the pressure, the better the refinement effect.

Application precautions for high shear homogenizer:

The ultra-fine crushing and emulsification functions of high shear homogenizers are unmatched by high-speed mixing, sanding, ball milling, colloid milling, ultrasonic and other homogenization equipment in terms of the quality of fineness and uniformity obtained from both theoretical and practical processing of emulsions and dispersions. However, if the process is not applied correctly or appropriately, satisfactory results cannot be obtained, at least it is impossible to achieve * effect.

The size of the pressure selected for homogenization processing determines the amount of energy obtained by the material. Generally speaking, the energy required for crushing should vary depending on the viscosity of the material, the surface tension of the liquid, and the final crushing fineness. Insufficient pressure is not enough, and excessive pressure is also unnecessary. The smaller the particle size of the material being crushed, the greater the energy required. Generally speaking, as the homogenization pressure increases, the average particle size of particles decreases, but the rate of particle size reduction slows down accordingly. This indicates that even with high pressure, the homogenizer's ability to grind fineness is not infinite. As for the current ordinary structure homogenizer, its ultimate crushing fineness is 0.2-0.2 μ m.

The initial particle size and uniformity of the material are important factors affecting the quality of homogenization. The process requires that the initial particle size of the material should not only be as small as possible (generally not greater than 20 μ m), but also undergo rough processing with low-energy homogenization equipment to make its particle size as uniform and consistent as possible. The uneven particle size of raw materials makes it difficult to obtain high-quality products during homogenization.

The content of oil and fat in the mixture is also one of the important factors determining its quality. When the energy density applied to the mixture is the same, an increase in oil content means a decrease in the average energy obtained by the unit, which directly affects the quality of the mixture. Experimental results have shown that within a certain range, reducing the proportion of oil is also one of the ways to increase homogenization effect, and the maximum proportion of oil content in the mixture should be less than 50%.

The viscosity of materials is also closely related to homogenization effect and homogenization efficiency. When the homogenization pressure is constant, the increase in material viscosity, such as from 2GP to 200GP, leads to an increase in material particle size. When the viscosity exceeds 200GP, the increase in particle size is particularly significant. Therefore, if the viscosity of the material is lower than 200GP, the homogenization effect is more effective. In terms of technology, a simple and effective method to reduce viscosity is to heat the material. For specific materials, such as resin emulsification, using oil to dissolve in a specific solvent can also conveniently and effectively reduce the viscosity of the oil.

There is also an issue of processing times in the homogenizer processing technology. The homogenizer only processes once, making it difficult for particles of different sizes to obtain the same energy, resulting in unsatisfactory uniformity. Experimental results have shown that during the homogenization process, large particles are more likely to obtain energy and be crushed into fine particles, while the reduction of fine particles is relatively difficult. Due to these two reasons, multiple homogenization processes are required in the manufacturing process. After several rounds of homogenization, not only did the particles gradually become smaller, but the particle size also tended to be consistent, greatly improving the homogenization effect. The maximum number of effective homogenization is nine times. If it exceeds nine times, the ratio of effectiveness to energy consumption will not be worth the loss.