Centrifugal Separators – Working Principle, Parts, Types, Uses

The most polluted water is found in stagnant bodies of water and wastewater treatment plants. The water and oil are filtered to produce pure water for consumption. This is accomplished using a variety of filters, with centrifugal separators being the most common. These filters are utilised to remove suspended particles and other contaminants from water.

A centrifugal separator is utilised in numerous industries, including brewing, animal feed production, pharmaceuticals, abrasives, and ceramics. They are employed to separate cream from milk, oil from water, sand from gravel, and paint pigments.

Centrifugal separators are driven by the centrifugation process. Using centrifugal force, centrifugation separates particles from a solution. This method is mostly used to separate two immiscible compounds present in a solution.

Working Principle of Centrifugal Separator 

It has an intake, an output, and a separator. In the separator, the liquid-solid, solid-liquid, or gas-solid mixture is injected into a cone-shaped working device. The spinning vortex produced by the separator facilitates the separation of solids from liquids. The separated solids are gathered at the separator’s base and discarded from there. High-density liquid and contaminants flow out of the separator, while low-density component remains inside. As one of the most thick liquids, water flows outside and is evacuated by a discharged outlet. However, fluids with a lesser density, such as oil, will remain in the vortex’s centre. From the separator’s suction opening, separated oil can be easily retrieved.

What Can a Centrifugal Separator Separate?

The effectiveness of centrifugal separation will depend on the disparity in the specific gravities of the filtering liquid and solid. This separation efficiency will be enhanced if the difference is significant. The particle size also affects the separation efficiency. For the majority of separators, 40 microns is the visibility threshold.

Instrumentation/Parts of Centrifugal Separators

The main parts of a centrifugal separator typically include:

1. Feed pipe: This is the pipe through which the mixture to be separated is fed into the separator.
2. Rotor: This is the central component of the separator that spins at high speeds, creating the centrifugal force needed to separate the substances.
3. Drive mechanism: This is the component that powers the rotor and keeps it spinning. It may be an electric motor, a gas engine, or some other type of power source.
4. Bowl: This is the container that holds the mixture as it is being separated. It is typically made of metal or a strong composite material.
5. Separation chamber: This is the area within the bowl where the separation process occurs.
6. Outlet pipe: This is the pipe through which the separated substances are discharged from the separator.
7. Scraper: This is a device that helps to remove the separated substances from the bowl or separation chamber.
8. Control panel: This is the component that allows the operator to control the operation of the separator, including adjusting the speed of the rotor and monitoring the performance of the separator.

Types of Centrifugal Separators

Centrifugal separators are mechanical devices that use the principles of centrifugal force to separate substances based on their size, shape, density, or other properties. There are several types of centrifugal separators, including:

1. Disc separators: These use a series of discs to separate solid particles from a liquid or gas. The particles are spun out to the edge of the discs and then collected.
2. Decanter centrifuges: These use a rotating drum to separate solid particles from a liquid or gas. The heavier particles are spun to the bottom of the drum, while the lighter particles rise to the top.
3. Scroll separators: These use a rotating scroll to separate solid particles from a liquid or gas. The particles are spun out to the edge of the scroll and then collected.
4. Hydrocyclones: These use a spinning motion to separate solid particles from a liquid or gas. The particles are spun to the outer edge of the hydrocyclone and then collected.
5. Disk stack centrifuges: These use a series of stacked disks to separate solid particles from a liquid or gas. The particles are spun out to the edge of the disks and then collected.

Operating Procedure of Centrifugal Separators

The operating procedure for a centrifugal separator will vary depending on the specific type of separator and the substances being separated. However, there are some general steps that are common to most separators:

1. Prepare the separator: This may include assembling the separator, attaching any necessary pipes or hoses, and making sure that all safety measures are in place.
2. Load the mixture: The mixture to be separated is fed into the separator through the feed pipe.
3. Start the separator: The separator is started by activating the drive mechanism, which powers the rotor and begins the separation process.
4. Monitor the separator: The operator should monitor the separator during the separation process to ensure that it is functioning properly and to make any necessary adjustments.
5. Discharge the separated substances: Once the separation is complete, the separated substances are discharged through the outlet pipes.
6. Clean and maintain the separator: After use, the separator should be cleaned and maintained to ensure that it continues to operate efficiently. This may involve cleaning the bowl or separation chamber, replacing any worn parts, and checking the condition of the rotor and drive mechanism.

Uses of Centrifugal Separator

It is available in a variety of configurations and capacities. Depending on their designs, they are utilised in various industries in various ways. Here are several uses for these separators:

• Pre-Filtration: When used for pre-filtration, the centrifugal separator increases the efficiency of filtration and reduces liquid loss. This pre-filtration allows users to save money on costly water treatment options.
• Protecting Heat Exchangers: They efficiently protect heat exchangers from fouling. The use of centrifugal separators makes it simple to eliminate scale and suspended grit.
• Protecting Spray Nozzles: It is also employed for covering spray nozzles and small orifices in a variety of industrial applications. How? These separators assist in removing sediments that clog spray nozzles. This, in turn, reduces wear and tear on the nozzle and prevents its frequent replacement.
• Reducing Industrial Waste: As is common knowledge, centrifugal liquid separators are intended to separate particles from a liquid. In applications where disposal costs are high or where recovery of high solids is required, this becomes advantageous. This also helps seals live longer lives.
• Preventing Debris Accumulation in Basins and Sump Wells: When utilised as part of the cooling system, the separators aid in preventing the accumulation of solids in basins and sump wells.

Advantages of Centrifugal Separators

It is utilised in a range of industrial applications due to the numerous benefits it provides. They feature fewer moving parts than other separators and lack filters, bags, screens, and cartridges, making them excellent for a variety of industrial applications. In addition to their design advantages, the following benefits are provided by these separators:

• Maintenance Free: Due to the lack of moving parts and other components, the centrifugal separator is practically maintenance-free. It is equipped with an automated purge valve designed to automatically flush away debris and pollutants.
• Minimal or No Downtime: This is another significant advantage of centrifugal separator water filters utilised in industrial processes. As filtration is accomplished by the rotation of a vortex, there are no actual filters involved. This means that there will be no collection of junk in filters, and thus no breakdown as a result. In addition, the filters will not need to be replaced as frequently as with conventional liquid separators.
• Minimal Liquid Loss: Did you know that purging with centrifugal separators results in less liquid loss than alternative filters? When cleaning sand media filters or automated strainers, users typically experience significant liquid losses.
• High Efficiency: In a single pass, the efficiency of centrifugal separation at 40 microns is 98%. For centrifugal separators, this measurement is 44 microns. This holds true for solids with a density of 2.6 and water with a density of 1.0.
• Compact size: Centrifugal separators are relatively compact, which makes them suitable for use in a variety of applications, including those where space is limited.
• Versatility: Centrifugal separators can be used to separate a wide range of substances, including liquids, gases, and solids. They can also be used to separate mixtures with a wide range of densities and particle sizes.
• Easy to operate: Centrifugal separators are relatively easy to operate, with most models having simple controls and a straightforward design.
• Reliability: Centrifugal separators are generally reliable and have a long service life, provided they are properly maintained.
• Cost-effective: Centrifugal separators are often more cost-effective than other separation methods, particularly for large-scale operations.
• Low environmental impact: Centrifugal separators have a low environmental impact compared to some other separation methods, as they do not generate hazardous waste or use harmful chemicals.

Disadvantages of Centrifugal Separators

Centrifugal separators are a widely used and effective method for separating substances, but they do have some limitations and drawbacks:

• High operating costs: Centrifugal separators require a lot of energy to operate, which can make them expensive to run.
• Limited separation range: Centrifugal separators are generally only effective for separating substances that have a significant difference in size, shape, or density. They may not be suitable for separating substances that are very similar in these properties.
• Complex design: The design of centrifugal separators can be complex, which can make them difficult to maintain and repair.
• Safety concerns: Centrifugal separators operate at high speeds and can generate a lot of heat and noise. They also pose a risk of injury if they are not used properly.
• Limited capacity: Centrifugal separators have a limited capacity, so they may not be suitable for separating large volumes of substances.
• Sensitivity to feed composition: The efficiency of centrifugal separators can be affected by the composition of the feed, so they may not be as effective if the feed contains impurities or other contaminants.

Areas of Application of Centrifugal Separators

Various businesses utilise it to separate two miscible chemicals. Listed below are some typical uses for these separators.

• Environmental Processes: It is utilised in many environmental procedures for the treatment of industrial and municipal wastewater. It is commonly employed to separate biomass and animal slurry from water.
• Recycling: Water contamination is one of the primary issues of many recycling plants. These centrifugal separators are utilised in recycling facilities for treatment and recovery processes. They are commonly utilised in a variety of industrial operations to recycle service water.
• Chemical and Plastic Processes: In the chemical industry, water is utilised in numerous processes of production. During chemical processes, a variety of byproducts are produced, which can pollute the water supply if they become diluted in water. During the process, the industrial centrifugal filters prevent pollution of water streams and collect intermediate or final products. Additionally, centrifugal separators are utilised in the production of plastics. They have numerous applications in the manufacturing of PP, HDPE, and PVC polymers. Similarly, these filters are utilised in the processing of minerals and ores, pharmaceutical and biotechnology industries, and non-fossil fuels, among others.
• Production of Food and Beverages: This business utilises a great deal of water and emits byproducts during numerous production steps. Here, centrifugal separators can be of assistance. They are utilised in the processing and recovery of non-liquid food products, the manufacturing of fruit and vegetable juices, and the processing of wine and sugar, among others.
• Oleo-Chemistry: Several byproducts are produced during the manufacturing of oleo-chemistry derivatives. Using centrifugal separators, they may be easily filtered. Additionally, these separators are utilised to refine edible vegetable oils. However, their use during the refinement of olive oil is not suggested.
• Mineral Fuel and Lubricating Oils: Industrial centrifugal filters are utilised for the purification and conditioning of mineral fuels, the purification of lubricating oils, as well as the treatment and recovery of various fuel oils. Additionally, they are utilised for the treatment of sludge oils from lagoons or refineries as well as bilge water.
• Animal-Based Items: The preparation of meat and fish generates numerous beneficial and non-useful byproducts. The centrifugal separators are utilised for the treatment of meat and fish processing wastes.
• Milk and Dairy Goods: These filters are utilised in the manufacturing of cheese and dairy products by the milk and dairy sector. Additionally, they are utilised to recycle waste materials.

Tips to Improve the Efficiency of Centrifugal Separators

The proper industrial centrifuge will enhance the effectiveness of your separation procedure. Due to the availability of several options, decision can be challenging. The following suggestions will facilitate your decision-making.

• Flow Rate: Although centrifugal separators separate using centrifugal force, their flow rates might vary. This equipment is rated in terms of pounds per hour. Flow rate is a crucial consideration when determining the size of the separator. If you select the separator based on characteristics such as piping, the separator’s rate may be significantly slower than planned. If this occurs, the filtration may not be effective or complete. To understand the flow rate, you may wish to consult the manufacturer. In addition, you must utilise the correct outlet/inlet size with the pipe to guarantee the centrifugal separator operates effectively.
• User-friendly Design: Modern centrifugal separators are available in a variety of configurations. However, it is not required that all websites have the same layout and be user-friendly. The optimal design is one that simplifies starting, cleaning, and maintenance for the user. Lakos centrifugal separators and filtration solutions, for instance, have user-friendly designs that enable users to ensure simple start-ups and cleaning, as needed. In cooling water towers, chillers, heat exchangers, and evaporative condensers, these proven systems filter airborne debris and suspended particles.
• Set the Appropriate Purge Timing: Many branded centrifugal separators, such as Lakos purge controllers, lack predetermined timings for the purge process. This is due to the fact that the duration and frequency of a purge may vary with solid concentrations, flow rates, particle kinds, etc. Therefore, the controller times must be set in accordance with the specifications. You can refer to the documentation included with the separator to determine the purge duration and other relevant parameters.
• Choose the Right Separator:  Separators from Lakos and other companies typically provide 15 to 25 years of service. However, this is insufficient. There are a number of additional factors that contribute to their longevity. For example, the construction material, fluid or chemical utilised, the environment in which it is used, the type of solids used for purging, and routine maintenance, etc. Therefore, while purchasing a new separator or upgrading an existing one, the manufacturer or supplier must be informed of their intended use.
• Maintenance: Like any industrial filtration equipment, centrifugal separators require maintenance to function properly. If proper maintenance is not performed, the machine may not perform as planned. Therefore, it is essential to undertake maintenance on a consistent basis. Regular maintenance can be obtained by contacting the manufacturer or the supplier. Always guarantee that the maintenance is handled by a seasoned specialist, as they fully comprehend the device’s specifications.