In modern industrial production, solid-liquid separation is a key processing technology, which is widely used in sewage treatment, chemical manufacturing, food processing, oil field mining and other fields. Among many separation equipment, the Decanter Centrifuge has become the first choice of many companies due to its compact structure, automated operation and high separation efficiency. The core secret of its efficient operation is the powerful centrifugal field brought by the “high-speed rotation” principle.
Basic principles of horizontal screw centrifuge
The essence of centrifugal force and separation
Horizontal screw centrifuge operates based on the principle of centrifugal sedimentation. When the mixed liquid containing suspended particles enters the high-speed rotating centrifuge drum, due to the density difference, the solid particles with higher density will be subjected to greater centrifugal force and quickly settle to the inner wall of the drum, while the liquid with lower density will be distributed inward, and finally achieve solid-liquid separation.
Double rotor structure of horizontal screw centrifuge
The horizontal screw centrifuge adopts a coaxial double rotor structure:
Bowl: The main component that rotates at high speed and generates strong centrifugal force.
Screw conveyor (Scroll): There is a slight speed difference with the drum, which continuously pushes the settled solid material to the slag outlet.
This unique structural design realizes the automatic and continuous discharge of solid materials, enabling the equipment to have the ability to operate uninterruptedly for a long time.
Core structure composition and function analysis
Although the horizontal screw centrifuge has a compact appearance, its internal structure is sophisticated and complex, and the various components are highly coordinated. The following are its main structural components and functions:
Drum system
Provides the basic carrier for centrifugal force, determines the maximum speed and separation factor;
Often made of duplex stainless steel or tungsten carbide wear-resistant materials;
It can be divided into a straight barrel section (sedimentation zone) and a conical section (dehydration compression zone), and the structural ratio has a great influence on the separation efficiency.
Screw conveyor
It rotates at a differential speed with the drum (generally 5~50 rpm);
The solids deposited on the inner wall of the drum are continuously pushed to the slag outlet;
The surface is mostly coated with carbide or ceramic patches to improve wear resistance.
Differential system
Controls the differential speed between the drum and the screw;
There are many forms such as mechanical differential speed, hydraulic differential speed, variable frequency electric differential speed, etc.;
The size of the differential speed directly affects the material residence time and slag dryness.
Feed and discharge system
The feed port is located in the center, and the material is evenly distributed inside the drum through the distributor;
The clear liquid is discharged through the overflow weir plate, and the solid is discharged from the slag outlet by the spiral propulsion;
The liquid level depth can be adjusted according to the viscosity of the material to balance the separation accuracy and processing volume.
Detailed explanation of the working process of Decanter Centrifuge
The operation process of Decanter Centrifuge can be divided into the following five stages:
Feeding
The material is transported to the feed pipe in the center of the centrifuge through the feed pump and dispersed into the drum under the action of the distributor.
Centrifugal sedimentation
The drum rotates at high speed to form a centrifugal field. The solid particles are quickly thrown to the outer wall under the action of centrifugal force, and the liquid is distributed to the inside.
Solid-liquid stratification
Due to the density difference, the liquid and solid are naturally stratified in the centrifugal field to form a “sandwich” structure: the outer layer is solid sediment, the middle layer is clarified liquid, and a small amount of fine solids may remain in the inner layer.
Screw conveying
The screw conveyor rotates at a different speed from the drum, pushing the outer layer of sediment to the end of the cone and discharged from the slag discharge port.
Liquid discharge
The clarified liquid overflows from the liquid outlet at the other end of the drum through the set liquid level weir plate to achieve stable liquid discharge.
This continuous, efficient and fully enclosed process not only ensures treatment efficiency, but also reduces human intervention and pollution risks.
The decanter centrifuge has become the backbone of the industrial solid-liquid separation field due to its efficient centrifugal force field brought by its high-speed rotation. It not only performs well in processing efficiency, operating stability, and environmental protection performance, but also continuously expands its application boundaries in the modern industrial system through continuous technological upgrades and intelligent innovations.
