Centrifugal Separators: Working Principle, Benefits, and Applications Discussed

Water is found in the most impure form at stagnant water bodies or wastewater processing plants. The water and oil is filtered to make pure water available for utilization. This is performed using various types of filters, of which, centrifugal separators are the most popular ones. These filters are used for the removal of suspended solids and other impurities in water.

A centrifugal separator finds application across industries such as breweries animal feed manufacturing, pharmaceutical manufacturing, abrasives, and ceramics. They are used to separate cream from milk, oil from water, sand from gravel, and pigments in paints. How do these separators work? What are the distinct features of these separators? How are they different from other separators? Read the post to know the answers.

What is Centrifugation?

Centrifugal separators are driven by the technique of centrifugation. Centrifugation utilizes centrifugal force to separate particles from the solution. This process is mainly employed to separate two immiscible substances existing in a solution.

Centrifugal Separator Working Principle

It features an inlet, outlet, and separator. The liquid-solid, solid-liquid, or gas-solid mixture is pumped into a cone-shaped working apparatus in the separator. The separator produces a spinning vortex, which leads to the filtration of solids from liquids. The separated solids are collected at the bottom of the separator, and they are purged from there. High-density liquid flows out of the separator, along with the contaminant, and low-density component will remain inside. Water is one of the denser liquids, so it flows outside, and is removed through a discharged outlet.  However, lower density fluids such as oil will remain at the center of the vortex. Segregated oil can be easily recovered from the suction orifice of the separator. 

Where Centrifugal Separator Used?

It is available in different designs and capacities. Depending on their designs, they are utilized in different ways across various industries. Here are a few applications of these separators:

• Pre-Filtration: The centrifugal separator helps improve the efficiency of filtration as well as minimize liquid loss when it is used for pre-filtration. This pre-filtration helps users save on expensive water treatment solutions.

• Protecting Heat Exchangers: They help protect heat exchangers effectively against fouling. Centrifugal separators can remove scale and suspended grit easily.

• Protecting Spray Nozzles: It is also used for protecting spray nozzles and small orifices in various industrial applications. How? These separators help remove solids that clog the nozzles of the spray. This, in turn, helps reduce the wear and tear of the nozzle, as well as avoid its regular replacement.

• Reducing Industrial Waste: As known centrifugal liquid separators are designed to remove solids from a liquid. This becomes advantageous in case of applications, where the disposal costs are high, or where recovery of high solids is mandatory. This also helps improve the life of seals.

• Preventing Accumulation of Debris in Basins and Sumps: When used as part of the cooling system, the separators help minimize the accumulation of solids in basins and sumps.

What Can a Centrifugal Separator Separate?

The efficiency of centrifugal separation will depend on the difference between the specific gravity of the liquid and the solid being filtered. This separation efficiency will increase if the difference is large. The separation efficiency is also affected by the particle size. For most separators, 40 microns is considered the visibility threshold.

Types of Centrifugal Separation

Centrifugal separators are mainly used for liquid-based applications. They are widely used to separate 

• liquid-solid suspensions

• liquid-liquid mixtures

• solid/gas-liquid mixtures

Advantages of Centrifugal Separators

It is used in a variety of industrial applications, owing to various advantages they offer. They have a few moving parts than other separators and have no filters, bags, screens, as well as cartridges, which makes them an ideal choice for various industrial applications. In addition to their design advantages, these separators provide the following benefits:

• Maintenance Free: The centrifugal separator is largely maintenance-free owing to the absence of moving parts or other components. It is fitted with an automatic purge valve designed to flush the debris and contaminants automatically.
• Minimal or No Downtime: This is another major advantage of centrifugal separator water filters used in the industrial process. As the filtration is performed by the spinning of a vortex, there are no real filters involved. This means there will no accumulation of debris in filters, and there will no breakdown due to this accumulation. Also, there will no need to change the filters more often, as in the case of other liquid separators.
• Minimal Liquid Loss: Do you know there is a little liquid loss by purging while using centrifugal separators than other filters! Typically, the users have to bear major liquid loses when cleaning sand media filters or automatic strainers.
• High Efficiency: The efficiency of centrifugal separation is 98% of 40 microns in a single pass. However, for centrifugal separator, this is 44 microns. This stands valid for solids at the gravity of 2.6 and water at 1.0.
• Lasting Performance: Owing to all the above-mentioned reasons, these centrifugal separators assure lasting performance than their industrial counterparts. Also, if you are sourcing them from brands such as Lakos, they assure 15–25 years of service. There are various factors that contribute to the longevity of these filters. They include the environment where the separator is being used, its material of construction, type of material being separated, and so on. Most times, industrial centrifuges are made of materials such as 304L/316L stainless steel or mild steel. Brands like Lakos provide them in metals such as chrome-moly, super duplex stainless steels, nickel alloys, Hastelloy, cupronickel, and other nickel alloys. All these metals are proven to assure durability and lasting performance in adverse environments.

Lakos SandMaster Plus, Stainless Steel Centrifugal Separator Sand Removal System

• Maximum System Pressure: 100 psi (6.9 bar)
• Maximum Temperature: 120 °F (49 °C)
• Purge Connection: ¾ inch male, N.P.T
• Flow Range: 5 - 70 U.S. gpm (19 - 265 m³/hr)
• Material of Construction: Plastic internal, stainless steel outer body

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Areas of Application of Centrifugal Separators

It is used in various industries for separating two miscible substances. The following are a few common applications of these separators.

• Environmental Processes: It is used in various environmental processes for industrial and municipal wastewater treatment. It is widely used for separating biomass and animal slurry from water.

• Recycling: Water impurities are one of the main concerns of various recycling plants. These centrifugal separators are used for treatment and recovery processes at recycling plants. They are widely used for recycling service water in various industrial processes.

• Plastic and Chemical Processes: In the chemical industry, water is used in various phases of chemical manufacturing. Various types of byproducts are generated during chemical processes which may get mixed with water, thereby polluting the water stream. The industrial centrifugal filters help avoid contamination of water streams and recover intermediate or end products during the process. Centrifugal separators are also used during plastic manufacturing. They find great applications during PP, HDPE, and PVC polymer production. Similarly, these filters are used in minerals and ores production, pharmaceutical and biotechnology sectors, and during the production of non-fossil fuels, among others.

• Food and Beverage Production: This industry uses a lot of water and also releases byproducts during various production processes. This is where centrifugal separators can help. They are used during the processing and recovery of non-liquid food products, fruit and vegetable juice production, wine and sugar processing, among others.

• Oleo-Chemistry: Several byproducts are generated during the production of oleo-chemistry derivatives. They can be easily filtered using centrifugal separators. These separators are also used for refining edible vegetable oils. However, they are not recommended to use during the refining of olive oil.

• Mineral Fuel and Lubricating Oils: Industrial centrifugal filters are used for purification and conditioning of fuels, purification of lubricating oils, and treatment and recovery of various fuel oils. They are also used for the treatment of slop-oils from lagoons or refineries or bilge water.

• Animal-based Products: The meat and fish processing creates lots of useful and non-useful byproducts. The centrifugal separators are used for the treatment of byproducts from meat and fish processing industries.

• Milk and Dairy Products: Milk and dairy industry utilizes these filters during the production of various cheese and dairy products. They are also used for recycling the waste materials.

Tips to Improve the Efficiency of Centrifugal Separators

The right industrial centrifuge will help improve the efficiency of your separation process. Owing to the availability of wide choices, the selection can be a difficult process. The following tips will make the selection easier for you.

• Flow Rate: Although centrifugal separators use centrifugal force to separate, their flow rates may vary. These equipment are rated by pounds per hour. The flow rate is one of the important factors for choosing the size of the separator. If you choose the separator based on the factors such as piping, then the separator may have a much slower rate than expected. If this happens, the filtration may not be complete or properly achieved. To understand the flow rate, perhaps, you can discuss with the manufacturer. Along with this, you need to use the appropriate outlet/inlet size with the piping to ensure the efficient functioning of the centrifugal separator.

• User-friendly Design: Centrifugal separators are nowadays available in different designs. However, it is not necessary that all have the same design, and assure user-friendliness. The ideal design is the one that allows a user to conduct startup, cleaning, and maintenance easily. For instance, Lakos centrifugal separators and filtration solutions feature user-friendly designs that allow users to assure easy start-ups and cleaning, whenever required. These designs are proven to filter airborne debris and suspended particles in cooling water towers, chillers, heat exchangers, and evaporative condensers.

• Set the Proper Purge Timing: Many branded centrifugal separators such as Lakos purge controllers do not have any set timings. This is because the purge duration and their frequency may depend on varying solid concentrations, flow rates, or types of solid particles, and so on. Thus, the controller times must be set according to the requirements. You can refer to the literature provided with the separator to set the purge duration and other details.

• Choose the Right Separator: Most times, the separators from Lakos and other brands assure 15-25 years of service. However, that is not enough. There are several other variables that contribute to their longevity. For instance, the material of construction, fluid or chemical used, an environment where it is used, type of solids used for purging, and regular maintenance, and so on. So, while purchasing the new separator or upgrading the existing one, all details about their utilization must be shared with the manufacturer or the supplier.

• Maintenance: Like any industrial filtration equipment, maintenance is essential for the proper functioning of a centrifugal separator. If maintenance is not properly performed, then the machine may not function as expected. So, it is important to perform maintenance on a regular basis. You can approach the manufacturer or the supplier for receiving regular maintenance. Always ensure that the maintenance is performed by an experienced professional because they perfectly understand the requirements of the device.

Now, you might have an idea of how a centrifugal separator works and how it helps separate different liquids. Thus, it is important to source them from a trusted manufacturer or a supplier. There are several centrifugal separator manufacturers and suppliers in US. Cannon Water Technology, Inc. is one of the industry-leading suppliers of centrifugal separators. The company stocks several types of centrifugal separators,  chemical feed systems for industrial uses.