Types of Mixing Equipments

Mixing equipment plays a vital role in various industries. Whether in chemical, pharmaceutical, food or other fields, efficient and reliable mixing equipment is indispensable. There are many types of mixing equipment, each with its own unique working principle and scope of application.

This blog will explore in depth the common types of mixing equipments, including their working principles, application areas, advantages and disadvantages, and provide some practical suggestions for selecting mixing equipment to help readers better understand and apply mixing equipment to improve production efficiency and product quality.

Definition of mixing equipment

A mixing equipment is a device that uses mechanical action or other external forces to make two or more materials evenly distributed at the molecular, particle or macroscopic level. From an engineering perspective, the mixing process usually involves the following key mechanisms:

• Convective mixing: the overall flow of materials

• Shear mixing: the speed difference between adjacent layers

• Dispersive mixing: the breakup of agglomerates

• Molecular diffusion: spontaneous movement at the molecular scale

Classification of mixing equipment

Classification by mixing method

According to the mixing method, mixing equipment can be mainly divided into three categories: mechanical mixing, gravity flipping and static mixer. Among them, mechanical mixing equipment includes paddle mixer, ribbon mixer, planetary mixer and anchor mixer; gravity flipping equipment mainly includes V-type mixer, double cone mixer and inclined drum mixer; static mixer includes pipeline and plate types.

To show these classifications more clearly, you can refer to the following table:

Classification by application fields of mixing equipment

In addition to classification by stirring method, application field is another classification standard for mixers. According to the classification of application field, mixing equipment can be divided into three categories: liquid mixing equipment, powder mixing equipment and emulsification equipment. Among them, liquid mixing equipment includes low-speed agitators, high-shear dispersers and homogenizers; powder mixing equipment mainly includes ribbon mixers, cone mixers and spiral mixers; emulsification equipment includes high-pressure homogenizers, emulsifiers and dispersers.

Detailed explanation of main mixing equipments

Homogenizer

A homogenizer is a device that mixes fluids of different phases (such as liquid-liquid or solid-liquid) and refines the particle size. It applies high pressure to make the fluid pass through a narrow gap, and uses shear force, turbulence and cavitation effects to make the fluids of different phases reach a uniform mixing state. The main components of the homogenizer include high-pressure plunger pumps, homogenizing valves and cooling systems.

Homogenizers can be divided into two categories: high-pressure homogenizers and ultra-high-pressure homogenizers. 

The working pressure of high-pressure homogenizers is usually between 10-60MPa, which is suitable for homogenizing foods such as dairy products and juices. The working pressure of ultra-high-pressure homogenizers can reach 100-350MPa, which is suitable for nano-level homogenization and emulsification, such as the preparation of nano-level drug carriers, cosmetics, etc. The following table lists the main differences between high-pressure homogenizers and ultra-high-pressure homogenizers:

The working principle of the homogenizer is as follows:

1. The material is pressed into the homogenizing valve by a high-pressure pump.

2. The material is accelerated in the narrow gap of the homogenizing valve to form a high-speed jet.

3. The high-speed jet hits the valve seat, generating strong shear force and turbulence, which refines and evenly mixes the material.

4. After the material passes through the homogenizing valve, the pressure drops sharply, generating a cavitation effect, which further promotes the refinement and homogenization of the material.

5. The homogenized material is cooled by the cooling system to prevent the material from deteriorating.

The application field of the homogenizer is very wide, including:

• Food industry: such as homogenization of dairy products, beverages, condiments, etc.

• Chemical industry: such as dispersion and homogenization of pigments, coatings, inks, etc.

• Pharmaceutical industry: such as homogenization and emulsification of drug preparations, vaccines, etc.

• Cosmetics industry: such as preparation and homogenization of emulsions, creams, etc.

The technical features of the homogenizer include:

1. Good homogenization effect: It can refine the fluids of different phases to the micron or even nanometer level, significantly improving the uniformity and stability of the system.

2. High energy consumption: Since the homogenization process requires high pressure, the energy consumption is high, but the energy consumption can be reduced by optimizing the design and operating parameters.

3. Clean and hygienic: The homogenizer adopts a fully enclosed design, which can achieve clean production and meet the hygiene requirements of the food, pharmaceutical and other industries.

4. Continuous production: The homogenizer can achieve continuous feeding and discharging, which is suitable for large-scale industrial production.

   
   

In order to further improve the homogenization effect and efficiency, the following measures can be adopted:

1. Optimize the design of the homogenization valve, such as using multi-stage homogenization valves, special materials and surface treatment, etc., to increase the shear force and turbulence intensity.

2. Use multi-stage homogenization, that is, the material passes through multiple homogenization valves in sequence, gradually refines and homogenizes, and improves the homogenization effect.

3. Combine other technologies, such as ultrasonic assisted homogenization, membrane homogenization, etc., to further improve the homogenization efficiency and uniformity.

4. Optimize process parameters, such as pressure, temperature, flow, etc., according to the material properties and product requirements, to improve the homogenization effect and efficiency.

Emulsifier

An emulsifier is a device that mixes two or more immiscible liquids and prepares a stable emulsion. The emulsification process refines the dispersed phase droplets and disperses them into the continuous phase through mechanical actions (such as shear, turbulence, etc.), and at the same time reduces the interfacial tension by adding emulsifiers such as surfactants to prevent the droplets from coalescing, and finally forms a stable emulsion. The main components of the emulsifier include emulsification barrel, agitator, homogenizing pump and cooling device.

Common types of emulsifiers are:

1. High shear emulsifier: It uses a high-speed rotating shear head to generate strong shear force and turbulence in the liquid, so that the droplets are refined and dispersed. It is suitable for liquid-liquid systems with low to medium viscosity. The shear head of the high shear emulsifier usually adopts a serrated or porous structure to increase the shear force and turbulence intensity.

2. Ultrasonic emulsifier: It uses the ultrasonic cavitation effect to generate tiny bubbles in the liquid. When the bubbles burst, they generate strong impact force and turbulence, which refines and disperses the droplets. It is suitable for high viscosity and nano-level emulsification. Ultrasonic emulsifiers are usually equipped with high-power ultrasonic generators and probes to achieve high-efficiency and high-uniformity emulsification.

3. Membrane emulsifier: It uses a microporous membrane to extrude and shear the dispersed phase into tiny droplets. It is suitable for preparing monodisperse and size-controlled emulsions. The membrane emulsifier can precisely control the particle size and distribution of the emulsion by adjusting parameters such as the membrane pore size, transmembrane pressure and shear rate.

4. High-pressure homogenization emulsifier: The pre-emulsion is pumped into the homogenization valve using a high-pressure pump, and the droplets are sheared, refined and dispersed under high pressure. It is suitable for high-viscosity and difficult-to-emulsify systems. High-pressure homogenization emulsifiers are usually equipped with multi-stage homogenization valves and cooling systems to achieve high-efficiency and high-uniformity emulsification.

5. Vacuum Emulsifying Mixer: Homogenization emulsification under vacuum conditions can effectively remove bubbles in the system and improve the stability and uniformity of the emulsion. The vacuum emulsifying mixer is usually equipped with components such as vacuum pumps, homogenization pumps and homogenization valves, which can achieve multiple functions such as degassing, homogenization and emulsification of the emulsion.

   
   

Characteristics and applications of different types of emulsifiers:

The application range of emulsifiers is very wide, such as food, cosmetics, medicine, pesticides, coatings and other industries, used to prepare various emulsion products, such as milk, cream, salad dressing, skin care products, medicinal emulsions, pesticide suspensions, etc.

When using an emulsifier, you need to pay attention to the following operating points:

1. Select appropriate emulsifying equipment and process parameters, such as speed, temperature, time, etc., and optimize them according to the properties of the raw materials and product requirements.

2. Control the raw material ratio and addition order, such as adding the continuous phase first and then the dispersed phase, which will help improve the emulsification efficiency and stability.

3. If necessary, emulsifiers, stabilizers and other additives can be added to improve the formation and stability of the emulsion. Commonly used emulsifiers include egg yolk lecithin, Tween, fatty acid glyceride, etc., and commonly used stabilizers include xanthan gum, carrageenan, carboxymethyl cellulose, etc.

4. Pay attention to temperature control during emulsification to avoid excessive temperature causing emulsion deterioration or demulsification. Generally, the emulsification temperature should not exceed 60°C, and heat-sensitive materials require lower temperatures.

5. After emulsification, post-treatments such as homogenization and sterilization can be performed to further improve the quality and stability of the emulsion. The homogenization pressure is generally 10-60MPa, the sterilization temperature is generally 110-130°C, and the time is 2-10 seconds.

   
   

In order to further improve the emulsification effect and efficiency, the following measures can be adopted:

1. Optimize the design of emulsification equipment, such as using special-shaped stirring paddles, multi-stage emulsification, high-pressure homogenization, etc., to increase shear force and turbulence intensity.

2. Optimize the emulsification process, such as two-step emulsification, microchannel emulsification, membrane emulsification, etc., to improve emulsification efficiency and uniformity.

3. Rationally select emulsifiers and stabilizers, such as selecting emulsifiers according to the hydrophilic-lipophilic balance value (HLB value), and selecting stabilizers according to the emulsion type and pH value to improve the formation and stability of the emulsion.

4. Use online monitoring and automatic control technologies, such as online particle size analysis, online viscosity measurement, automatic batching and temperature control, to achieve real-time optimization and quality control of the emulsification process.

Mixer

A mixer is a device that mixes two or more materials and achieves uniform dispersion. It is widely used in multiphase mixing processes such as solid-solid, liquid-liquid, and gas-liquid. The structural features of the mixer include:

1. Mixing barrel: used to hold the materials to be mixed, and the shape and size are determined according to the process requirements and production scale. Common mixing barrel shapes include cylindrical, conical, square, etc., and the materials include stainless steel, enamel, fiberglass, etc.

2. Agitator: installed in the mixing barrel, the materials are mixed and dispersed through rotational motion. Common types include paddle type, anchor type, spiral ribbon type, etc. The geometric shape, size and layout of the agitator have an important influence on the mixing effect.

3. Drive device: provides the power required by the agitator, such as motor, reducer, etc. The power, speed and transmission mode of the drive device need to be selected according to the scale and process requirements of the mixer.

4. Inlet and outlet device: used for the addition and discharge of materials, such as manholes, valves, pumps, etc. The position, size and type of the inlet and outlet device need to be designed according to the nature of the material and production requirements.

   
   

The working principle of the mixer is to generate shear force, turbulence and convection in the material through the rotational motion of the agitator, so that the material is continuously dispersed and mixed, and finally reaches a uniform distribution state. The type and structure of the agitator have an important influence on the mixing effect, and it needs to be selected and optimized according to the material properties and process requirements. Common agitator types and characteristics are shown in the following table:

Mixers are suitable for a wide range of materials, including:

• Powdered and granular solid materials, such as powders, granules, fibers, etc. Commonly used solid-solid mixers include V-type mixers, double cone mixers, ribbon mixers, etc.

• Liquid materials, such as solutions, suspensions, emulsions, etc. Commonly used liquid-liquid mixers include paddle agitators, static mixers, emulsifiers, etc.

• Gaseous materials, such as air, steam, etc., are used to achieve gas-liquid mixing. Commonly used gas-liquid mixers include bubbling agitators, tubular static mixers, jet mixers, etc.

The efficiency of the mixer mainly depends on the following factors:

1. Mixing mechanism: Different mixing mechanisms (such as convection mixing, shear mixing, diffusion mixing, etc.) correspond to different mixing efficiencies. Convection mixing mainly relies on the macroscopic flow of materials to achieve mixing, shear mixing mainly relies on shear force to destroy material agglomeration to achieve mixing, and diffusion mixing mainly relies on the microscopic movement of materials to achieve mixing.

2. Agitator type: Choosing the right agitator type (such as paddle type, anchor type, ribbon type, etc.) can significantly improve the mixing efficiency. The geometry, size and layout of the agitator will affect the mixing effect.

3. Stirring speed: The higher the stirring speed, the higher the mixing efficiency, but too high a speed may cause the material to break or deteriorate. The stirring speed needs to be optimized according to the material properties and mixing requirements. Generally, a dimensionless number (such as thunder

Conclusion

In short, there are many types of mixing equipment, each with its own unique working principle and application field. Understanding the characteristics and advantages of different mixing equipment, selecting suitable equipment and optimizing process parameters are essential to improving mixing efficiency and product quality.

Wejing's emulsifying mixer adopts advanced design and manufacturing technology, has excellent performance, is widely used in food, cosmetics, medicine and other industries, and is deeply trusted by customers. If you need help with selection and application, please contact Wejing, we will wholeheartedly provide you with professional technical support and services.