Should a vacuum emulsifier choose bottom homogenization or external circulation homogenization?

I. What is a Vacuum Emulsifier?

A vacuum emulsifier is a high-efficiency production equipment that integrates heating, stirring, homogenization, emulsification, vacuum degassing, and cooling functions.

During the production process, oil phase, water phase, or other raw materials are pre-treated and then enter the emulsification tank. Stirring and high-speed homogenization are carried out in a vacuum environment, allowing liquid phases, oils, and active ingredients of different properties to be fully mixed, forming a stable, uniform, and fine emulsion product.

The vacuum environment plays a crucial role. On the one hand, it reduces the amount of air entering the product during production, reducing bubble formation; on the other hand, it improves the product's appearance and texture and reduces the risk of oxidation of some raw materials during high-speed stirring.

Therefore, vacuum emulsifiers are widely used in:

Cosmetics Industry
Skincare Industry
Daily Chemical Industry
Pharmaceutical Industry
Food Industry
Toothpaste and Paste Industry
Fine Chemical Industry

Common products include face creams, lotions, serums, body lotions, toiletries, ointments, gels, toothpaste, sauces, etc.

II. What is Bottom Homogenization?

Bottom homogenization is a common homogenization structure in vacuum emulsifiers.

As the name suggests, the bottom homogenizer is installed at the bottom of the emulsification tank. When the equipment is running, the material circulates downwards under the action of the stirring system and enters the bottom homogenizer.

The high-speed rotating homogenizing head further disperses and refines larger droplets or particles through high-speed shearing, centrifugation, collision, and turbulence, before the material re-enters the emulsification tank to continue mixing with the material inside.

In simple terms, its working process can be understood as follows:

Raw material enters the emulsification tank → Stirring and mixing → Material enters the bottom homogenizer → High-speed shearing dispersion → Material re-enters the emulsification tank → Continuous circulating emulsification.

Key Features of Bottom Homogenization

1. Compact Structure

The homogenizer is directly installed at the bottom of the emulsification tank, eliminating the need for long external circulation pipelines, resulting in a relatively compact overall structure.

2. Relatively Small Footprint

For companies with limited production space, bottom homogenization solutions can reduce the need for external equipment and piping.

3. Relatively Simple Operation

The homogenization system is directly integrated with the emulsification tank, making the equipment operation logic relatively intuitive and suitable for routine emulsification production.

4. Easier to Control Overall Costs

Due to its relatively simple structure, bottom homogenization solutions typically offer better economic efficiency for the same production capacity.

III. What is External Circulation Homogenization?

External circulation homogenization, also known as an external circulation homogenization system, is characterized by placing the homogenizer outside the emulsification tank.

During production, material in the emulsification tank enters the circulation pipeline through the bottom outlet and enters the external homogenizer under the pressure of the circulation pump or system pressure.

After high-speed homogenization, shearing, and dispersion, the material returns to the emulsification tank through the return pipeline.

Its basic working process is:

Emulsification tank → Outlet pipeline → External circulation homogenizer → High-speed shearing dispersion → Return pipeline → Emulsification tank → Continuous circulation.

Compared to bottom homogenization, the biggest advantage of external circulation homogenization is that it can form a more defined and stable external circulation emulsification path.

Main characteristics of external circulation homogenization:

1. High circulation efficiency

Material can continuously enter the external homogenizer from the tank and then return to the tank, which helps improve the overall homogenization and circulation efficiency of the material.

2. Stable Homogenization Effect

For products requiring high fineness and uniformity, external circulation homogenization allows for continuous circulation, enabling more material to pass through the homogenizer.

3. Convenient Observation and Maintenance

The homogenizer is installed externally, which is more convenient for maintenance and repair in certain scenarios compared to structures completely installed inside the tank or at the bottom.

4. Suitable for High-Requirement Emulsification Processes

For products with high requirements for particle size, fineness, uniformity, and stability, external circulation homogenization is a worthwhile solution.

IV. What is the difference between bottom homogenization and external circulation homogenization?

This is one of the most crucial questions customers ask when choosing a vacuum emulsifier.

V. Which Products Are Suitable for Bottom Homogenization?

Bottom homogenization is suitable for high-volume, conventional emulsification production scenarios.

For example:

1. Face Creams and Lotions

For most conventional face creams, body lotions, hand creams, etc., bottom homogenization can meet basic emulsification and dispersion needs.

2. Regular Emulsions

For skin lotions, body lotions, shampoo and conditioner lotions, material mixing and emulsification can be achieved through stirring and bottom homogenization.

3. Daily Chemical Products

Some shampoos, shower gels, hair care products, etc., can also use bottom homogenization if the specific formula allows.

4. Projects Sensitive to Equipment Investment

If the client has specific requirements regarding equipment budget, and the product does not have particularly high requirements for homogenization processes, bottom homogenization can be considered an economical solution.

VI. Which Products are Suitable for External Circulation Homogenization?

If a product has high requirements for emulsification, fineness, stability, and uniformity, external circulation homogenization should be considered.

1. High-end Skincare Products

For example, high-end face creams, serums, and anti-aging products have high requirements for product texture and stability.

2. High-Viscosity Products

Some high-viscosity creams, ointments, and pastes require more thorough circulation and homogenization.

3. Products with High Requirements for Emulsification Fineness

If customers require a finer, more uniform texture, external circulation homogenization can further optimize the production process.

4. Mass Production

For projects with large production volumes, a well-designed circulation pipeline and homogenization system can improve overall production efficiency.

VII. Bottom homogenization versus external circulation homogenization: Which emulsification method yields better results?

This is a common point of misunderstanding for many customers.

Emulsification effectiveness cannot be judged solely by the homogenizer's installation location.

The final emulsification effect is also related to the following factors:

Homogenizer structure
Homogenization speed
Homogenization power
Agitation method
Agitation speed
Material viscosity
Raw material ratio
Temperature
Vacuum level
Emulsification time
Tank structure
Product formulation

For example, a well-configured bottom homogenizing vacuum emulsifier can fully meet the production needs of large quantities of ordinary cosmetics and daily chemical products.

However, for some high-viscosity, high-requirement emulsified products, external circulation homogenization offers a more flexible circulation process.

Therefore, equipment selection should be based on the actual product process, rather than simply pursuing a particular homogenization structure.

VIII. How to Choose Between Bottom Homogenization and External Circulation Homogenization Based on Product?

The following approaches can be used to determine the best choice:

Scenario 1: Product is a common lotion or cream

If the product formula is mature and doesn't require extremely fine emulsification, bottom homogenization can be prioritized.

Scenario 2: Product has high viscosity

For high-viscosity creams, ointments, etc., it's recommended to have the equipment manufacturer conduct tests based on the actual materials before deciding between bottom homogenization and external circulation homogenization.

Scenario 3: Product requires very fine texture

For example, high-end skincare products and products with special emulsification, external circulation homogenization should be considered.

Scenario 4: Requires a high degree of automation

Both solutions can be equipped with PLC automatic control, touch screens, automatic temperature control, vacuum control, and automated production programs.

Therefore, the degree of automation is not the only criterion for choosing between bottom homogenization and external circulation homogenization.

Scenario 5: Requires future production line expansion

If there are plans to expand production capacity, add automation functions, or connect to the filling production line in the future, the external circulation system can be designed with more flexible piping based on the production process.

IX. Why Do Vacuum Emulsifiers Need to be Customized?

Different customers produce different products, and therefore have different equipment requirements.

Therefore, professional vacuum emulsifiers are usually not simple "standard equipment," but need to be configured according to the customer's actual production needs.

Customization typically requires confirmation of the following:

1. Production Capacity

For example, 100L, 200L, 500L, 1000L, 2000L, etc.

2. Product Type

It needs to be specified whether the product being produced is a face cream, lotion, serum, toothpaste, ointment, or other product.

3. Material Viscosity

Different viscosities require different stirring and homogenization configurations.

4. Homogenization Method

Based on the product process, bottom homogenization, external circulation homogenization, etc., are selected.

5. Stirring Method

Different solutions can be configured according to product characteristics, such as frame stirring, wall-scraping stirring, anchor stirring, etc.

6. Heating and Cooling Method

Based on the production process, electric heating, steam heating, and corresponding cooling systems are selected.

7. Vacuum System

Configure a suitable vacuum pump and vacuum control system according to product process requirements.

8. Automation Level

PLC control system, touch screen, and automated production program can be configured according to customer needs.

Conclusion: Which should you choose?

There's no single, definitive answer to whether to choose bottom homogenization or external circulation homogenization for a vacuum emulsifier.

If your product is a common face cream, lotion, or daily chemical product, and you are concerned about equipment structure, footprint, and investment costs, bottom homogenization is usually a practical choice.

If your product requires high levels of fineness, uniformity, emulsification stability, and circulation capacity, especially if it involves high-viscosity or high-end emulsified products, external circulation homogenization is worth considering.

Most importantly:

Don't choose external circulation homogenization simply to get "more advanced" equipment, nor should you choose bottom homogenization just to reduce costs. Truly suitable equipment should be customized based on product formulation, material viscosity, production capacity, emulsification process, and target production capacity.

If you are purchasing a vacuum emulsifier, vacuum homogenizing emulsifier, or a complete cosmetic production system, you can provide the equipment manufacturer with your product type, production capacity, material viscosity, and target production capacity. A professional engineer will then recommend a bottom homogenization or external circulation homogenization solution based on your actual process, thus avoiding equipment mismatch issues.