Decanter Centrifuges

Decanter Centrifuges, also known as Solid Bowl Centrifuges or Horizontal Bowl Centrifuges, are a type of mechanical dewatering equipment designed to continuously separate solids from liquid in a slurry using centrifugal force at high G’s.


How Decanter Centrifuges Work

Slurries may be separated into solid and liquid phases by a process known as sedimentation, where gravity forces cause the heavier solid particles to settle out from the less dense liquid. The rate of sedimentation can be greatly increased by Decanter Centrifuges, which use centrifugal sedimentation to continuously separate slurries quickly and effectively.

The slurry is fed, along with polymer to aid in sedimentation, into the inside of a helical screw conveyor that is fitted inside and closely conforming to a bowl that rotates at high speed. A gearbox rotates the conveyor at a slightly lower speed than the bowl. The slurry emerges into the region between the conveyor and the bowl through feed ports cut through the conveyor.

Centrifugal forces cause the solid particles to sediment outward toward the inside surface of the bowl, while the lighter liquids float on the inside of this solids cake. The conveyor pushes the sedimented solids toward one end of the bowl, while the liquid flows freely toward the other end.

At the solids discharge end, the bowl and conveyor are conically tapered inward so that the conveyor lifts the solids out of the pool of liquid and ejects them out of the bowl through the radial discharge ports, while still retaining the liquid. The liquid exits the bowl from ports with adjustable weirs at the other end of the machine.

The solids and liquid ejected from the bowl discharge ports are collected into a stationary casing, which incorporates baffle plates to prevent remixing. Discharge chutes or hoppers are attached under the casing to collect the separated material. The solids are usually collected on a conveyor, and the liquid is piped away.

Why McLanahan Decanter Centrifuges

McLanahan Decanter Centrifuges are available in a range of sizes and capacities to suit a variety of materials in many different applications. They offer high separation of solids and liquids producing a low moisture content solids discharge between that achieved by a Thickener and a Filter Press. The liquid recovered can be recycled back into the process reducing overall demand.

Decanter Centrifuges from McLanahan can be used for solids recovery to capture valuable products from a liquid stream or to reduce the volume of material reporting to settling ponds, reducing the size requirements for the ponds or eliminating the need for them altogether. In this regard, McLanahan Decanter Centrifuges offer a sustainable solution to pond reduction/elimination and water recovery in areas where water is scarce, or expensive, or space for traditional settling lagoons is not available or at a premium. This may also help with environmental permitting and regulations.

McLanahan Decanter Centrifuges are compact, easy to operate and have a small footprint. They offer long service life with minimal maintenance requirements. 

Frequently Asked Questions About Decanter Centrifuges

Ask An Expert

Decanter Centrifuges are used to separate solids from liquid in a slurry in a wide variety of applications, including food processing, oil refining, waste recycling, chemical extraction, mineral processing, aggregate processing and more.

Decanter Centrifuges are available in a range of sizes and capacities. Because of this, the cost of a Decanter Centrifuge can vary enormously depending on the type and size of Centrifuge needed to fit the application requirements. Once a duty is determined, McLanahan engineers will be able to select a suitable model and provide cost and cost benefit information accordingly. 

Decanter Centrifuges and Disc Centrifuges are both types of mechanical equipment used for liquid/solids separation and dewatering using centrifugal forces. The main difference between the two is that Decanter Centrifuges (also known as Horizontal Bowl Centrifuges) rotate around a horizontal axis while Disc Centrifuges (also known as Vertical Bowl Centrifuges) rotate around a vertical axis. The Disc Centrifuge generates a much higher G-force than Decanter Centrifuges.

Other differences between Decanter Centrifuges and Disc Centrifuges include the footprint, power requirement, separation efficiency and allowable feed solids.

Decanter Centrifuges are ideal for slurries with high solids content and large particle sizes. Disc Centrifuges are ideal separating fine particles from a slurry or for separating two different liquids of similar specific gravities.

Belt Filter Presses may be used in similar applications to Decanter Centrifuges. By comparison, a Centrifuge will produce a drier cake and has a higher capacity with a smaller footprint.

Other advantages of a Centrifuge over a Belt Filter Press include:

  • Fully automated operation, meaning less operator intervention required
  • Lower volume cake, reducing storage area/transport requirements
  • Enclosed operation for cleaner/ less housekeeping
  • Less sensitivity to changing feed characteristics, meaning less adjustment
  • Longer maintenance intervals (belt filters can require frequent replacement)
  • No requirement for continuous wash water, so less water is required
  • Simple, heavy-duty construction

McLanahan Decanter Centrifuges are compact, easy to operate and have a small footprint

Features & Benefits
  • Easy to operate
  • Small footprint
  • Low cake moisture
  • High removal of solids
  • Long service life
  • Large capacity
  • Fully automated

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