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Centrifugation is to use the strong centrifugal force generated by the high-speed rotation of the centrifuge rotor to accelerate the sedimentation rate of particles in the liquid and separate substances with different sedimentation coefficients and buoyancy densities in the sample. Therefore, it is necessary to use a centrifuge to generate a strong centrifugal force to force these particles to overcome diffusion and produce sedimentation movement. Maximize efficiency and accuracy in your lab with the power of centrifugation. By utilizing the high-speed rotation of the centrifuge rotor, you can separate different substances based on their sedimentation coefficients and buoyancy densities, resulting in faster sedimentation rates. With centrifugation, you can overcome diffusion and produce sedimentation movement efficiently and effectively.
The centrifuge has a cylinder that rotates at high speed around its own axis, called a drum, which is usually driven by an electric motor. After the suspension (or emulsion) is added to the drum, it is quickly driven to rotate at the same speed as the drum. Under the action of centrifugal force, the components are separated and discharged separately. Generally, the higher the drum speed, the better the separation effect. Achieve optimal separation results with the centrifuge’s high-speed rotating drum. Designed with a powerful electric motor, it quickly drives the drum to match its rotation, using centrifugal force to efficiently separate and discharge components.
Centrifugation is to use the strong centrifugal force generated by the high-speed rotation of the centrifuge rotor to accelerate the sedimentation rate of particles in the liquid and separate substances with different sedimentation coefficients and buoyancy densities in the sample. Centrifuges are widely used in chemical, petroleum, food, pharmaceutical, mineral processing, coal, water treatment and shipbuilding sectors. What are the categories of centrifuges? Expand your knowledge in various fields with the use of centrifuges. These powerful machines, which utilize centrifugal force through high-speed rotation, have the ability to rapidly separate substances based on their sedimentation rates and buoyancy densities. They are essential tools in chemical, petroleum, food, pharmaceutical, mineral processing, coal, water treatment, and shipbuilding industries. What categories of centrifuges are you most interested in learning about?
Industrial centrifuges can be divided into three categories according to their structure and separation requirements: filtration centrifuges, sedimentation centrifuges and separators.
一、Filter Centrifuge
Centrifuges that achieve centrifugal filtration and rely on filter screens and centrifugal force are filtering centrifuges.
Structural features: filter screens, drums.
Principle of filtering centrifuge: There are many small holes on the drum wall, and there is a filter screen (filter cloth) inside the wall. The suspension rotates in the drum, and the liquid phase is thrown out of the screen by centrifugal force, while the solid phase particles are retained by the screen to form a filter cake, thereby achieving solid-liquid separation. With a centrifuge, solid-liquid separation is a breeze. By rotating the suspension in the drum and throwing out the liquid phase with centrifugal force, the solid phase is retained to create a filter cake.
Scope of application: Suspensions with high solid content and large solid particles (d > 10μm).
1. Three-column filter centrifuge:
A manual top loading centrifuge.
Widely used in: chemical, pharmaceutical, food, light industry and other industries.
Structure: drum, filter, main shaft, bearing, chassis, shell, three pillars, belt drive, motor, etc.
Operation principle during unloading
Working order: start, add, filter, wash, spin, stop, unload. Periodic, intermittent operation. The suspension is gradually added to the drum after starting. Under the action of the centrifugal field, the liquid is thrown out through the filter cloth (filter screen) and the drum hole, and the solid is trapped in the filter screen to form a filter cake. The machine operates efficiently and effectively with periodic and intermittent operation. It also includes a suspension system that gradually adds liquid to the drum after starting. The centrifugal force then separates the liquid from the solid through the filter cloth and drum hole, leaving behind a solid filter cake.
Advantages:
⑴ Strong adaptability to materials, can be used for solid-liquid separation, finished product deliquidation, and filter cake washing.
⑵ Simple structure, low manufacturing, installation, maintenance and use costs. Easy-to-use, cost-efficient, and durable. This product is perfect for any budget-conscious consumer.
⑶ Smooth operation, easy to achieve airtightness and explosion-proof. This product features advanced technology and precise engineering for smooth operation and reliable airtightness. It meets strict industry standards for explosion-proof safety.
Disadvantages: Stopping the machine for unloading, low efficiency. One downside to this machine is having to stop and unload it frequently, which may negatively impact efficiency. However, its other features and capabilities more than make up for this minor inconvenience.
2. Top-hung centrifuge
Working cycle: feeding, filtering, washing, separation and unloading at high speed. “The product features a highly efficient working cycle, including feeding, filtering, washing, separation, and unloading. With its high speed capabilities, it provides quick and effective results for your work process.”
Working characteristics: high-speed continuous operation, intermittent feeding and unloading. Can handle suspensions of coarse, medium and fine particles.
Structure: drum, filter, feeding pipe, scraper mechanism, unloading chute, shell, main shaft, body, motor. This industrial-grade centrifuge expertly separates solids from liquids in a precise and efficient manner. With a main shaft, motor, drum, scraper mechanism, and unloading chute, it’s a comprehensive solution to all your needs.
Widely used in: chemical, pharmaceutical, light industry, food and other industries. Such as: salt, ammonium sulfate, ammonium bicarbonate, polyvinyl chloride, etc.
Application
Advantages: ① Strong adaptability to materials. Suspensions of coarse, medium and fine particles can be processed.
② The time of filtering, washing, separation and unloading processes can be adjusted arbitrarily.
③ Continuous operation, uniform speed and high efficiency.
Disadvantages: The scraper wears quickly and is prone to impact. The scraper blade is most easily damaged by wear, impact and corrosion during operation, so it is necessary to use wear-resistant, corrosion-resistant and high-strength materials. The scraper blade is designed to withstand high impact and wear, ensuring the longevity of this important tool. This is achieved through the use of durable and corrosion-resistant materials, making it a reliable and long-lasting addition to your equipment.
Scraper structure: ① Top-hung scraper. ② Rotating scraper. Expertly designed for maximum efficiency and performance, this scraper features both a top-hung and rotating design. This dynamic combination ensures thorough cleaning and removal of even the toughest debris, providing lasting results for your business.
二、 Decanter Centrifuge
The drum does not contain any holes or filters and is rotated at high speed by the suspension. This creates varying centrifugal inertial forces due to the different specific gravities of the solid and liquid phases. The solid particles with the strongest centrifugal force are deposited on the inner wall of the drum while the liquid phase settles in the inner layer. The separated components are then discharged from different outlets.
The decanter centrifuge generally has a higher speed: n=7000~8000rpm
Applicable range: less solid content, smaller solid particles (d < 10 μm).
Common models: spiral discharge type.
Divided into:
⑴ Screw discharge type decanter centrifuge (including: horizontal; vertical)
⑵ Scraper discharge horizontal decanter centrifuge
⑶ Three-legged decanter centrifuge
1. Screw discharge decanter centrifuge
Widely used in: chemical industry, petroleum, metallurgy, pharmaceutical, light industry, food, sewage treatment, etc., to treat suspensions with particle size d<10μm.
Working characteristics: continuous feeding, separation, unloading, full speed operation, high speed n=7000~8000rpm.
The drum operates by allowing the suspension to enter from the center, forming a circular liquid pool under the influence of centrifugal force. The heavy phase particles settle on the inner surface of the drum and are pushed towards the small end by the spiral blades for discharge. A circular arrangement of overflow holes on the large end cover allows for the discharge of clarified liquid.
The primary operational factors include: drum velocity, difference in speed between the drum and feeding screw, positioning of the overflow port, and feeding velocity; the main structural factors consist of: drum diameter at the large end D, drum length ?L, ratio of length to diameter L/D, semi-cone angle of the drum α, and number of spiral heads and pitch of the feeding screw.
Main benefits: automated continuous operation, no need for filter cloth, long-term ease of use, simple maintenance; wide application range for solid deliquification, liquid clarification, solid particle size classification, and liquid-liquid-solid separation; versatile material adaptability, capable of separating solid particles ranging in size from 0.005mm to 2mm and suspensions with a volume concentration of 2%-40%; minimal impact from concentration fluctuations on separation efficiency; compact structure allows for easy structural sealing and operation under positive pressure; high production capacity per machine (up to 190m3/h), low operating costs, and small footprint.
When considering this product, it’s important to note that the sediment often contains a high liquid content. While it is possible to wash the sediment, the effectiveness of this process may be limited. Additionally, the structure of the product is complex and may contribute to its higher cost.
2. Sedimentation-filtration centrifuge
Drum: Divided into sedimentation section and filtration section
（1）Sedimentation section: There are two types of forms: cylindrical and conical; full cone.
Function: The suspension enters the sedimentation section for sedimentation separation, and the clarified liquid overflows from the large end overflow hole; the sediment is transported to the filtration section by the screw conveyor for filtration and dehydration.
（2） Filtration section: The form is cylindrical, with filter screen and sieve holes.
Filtering is performed on the sediment using the screen in this section, causing separation of the liquid and discharge of the filter residue from the large left end hole. In case washing or drying is necessary for the filter residue, it can be accomplished by passing washing liquid or steam through the center hole located in the filtration section.
The screen is refreshed by passing compressed air or clean water through the backflush pipe in order to backflush it.
3. Spiral-disc centrifuge
Mechanism: It consists of two parts: a horizontal spiral discharge centrifuge and a butterfly separator.
Function: The spiral discharge centrifuge separates solids and liquids; the butterfly separator further processes the liquid to obtain a liquid product with a high degree of clarity.
Drum: It consists of two parts: the main separation chamber and the auxiliary separation chamber.
Main separation chamber: It is a horizontal spiral centrifuge, which mainly separates solids and liquids. Most of the solid particles are separated and discharged by the spiral conveyor.
Auxiliary separation chamber: It is a butterfly separator, which further separates the liquid and separates finer particles.
Working principle: The spiral centrifuge section receives the suspension through the central tube, which then separates solid particles from the liquid through high-speed centrifugal force. The resulting sediment is expelled through a small discharge hole at the end of the conveyor.
The liquid enters the butterfly separator from the overflow hole at the large end of the centrifuge, and the solid-liquid separation is performed again. The fine particles are discharged from the peripheral holes, and the highly clarified liquid is discharged from the middle overflow hole.
三、Separator
Working principle: According to the density difference between the liquid-liquid phases, the liquid-liquid phases are separated under high-speed centrifugal force field, with the heavy phase in the outer layer and the light phase in the inner layer, and then discharged separately to achieve the purpose of separation. It utilizes high-speed centrifugal force field to effectively separate the liquid-liquid phases based on their density difference, discharging them separately in outer and inner layers for efficient separation.
Scope of application: emulsion separation, emulsion containing trace solid particles (d<5 μm)
Common models: tubular separator, chamber separator, disc separator.
Application: oil, paint, pharmaceutical, chemical, etc.
Such as: oil-water separation, protein, penicillin, essential oil, etc.
Disc separator
The vertical centrifuge disc separator has a drum stacked with disc-shaped parts that rotate at high speed due to an electric motor and transmission device. A small gap between the discs allows for the addition of suspension or emulsion through a feed pipe at the center of the drum. Under the influence of centrifugal force, solid particles or droplets settle on the discs to form sediment or a liquid layer. The sediment is then removed manually or through a slag discharge mechanism. Meanwhile, the separated liquid flows out of the drum through a liquid outlet.
The main operating parameters of the disc separator are: drum speed, light liquid speed, position of the interface between light liquid and heavy liquid, feeding speed, etc.; the main structural parameters of the stacked separator are: drum inner diameter, equivalent sedimentation area, disc size and total number of discs, slag discharge method and slag discharge mechanism. With a disc separator, you’ll have the flexibility to adjust key parameters such as drum speed and light liquid speed, ensuring optimal performance according to your needs. You’ll also appreciate the unique features of a stacked separator, including an efficient drum inner diameter and generous equivalent sedimentation area for consistent results. The slag discharge process is equally streamlined for easier operation.
The disc centrifuge has a compact structure, small footprint, large production capacity, and is suitable for liquid-solid and liquid-liquid separation. Therefore, it is widely used in chemical, pharmaceutical, light industry, food, bioengineering and transportation sectors.
The disadvantage of the butterfly separator is that it has a complex structure and high speed, so the operation and maintenance requirements are relatively high, and it is more troublesome to clean.
In summary, centrifuges play an important role in laboratories through their unique working principles and perfect system design. With the continuous development and progress of science and technology, the performance and functions of centrifuges will continue to improve and improve to meet a wider range of experimental needs.