An industrial centrifuge with a stack of cone-shaped discs that has been specially designed is called a disc stack centrifuge. The extra surface shortens the settling distance and multiplies the settling area.
Read More: disc stack separator
These characteristics, along with the high g-force (7,000 Gs), make this centrifuge an extremely effective tool for separating immiscible liquids and fine particles (0.5µm).
Remember that there are other names for a disc stack centrifuge, including disc bowl, conical plate, disk stack, and disc stack separator.
The Operation
Immiscible liquids and suspended solids are separated from contaminated fluids using a disc-stack centrifuge. Particles settle on the disc surface due to G-forces of up to 10,000 Gs, where they flocculate and travel toward the centrifuge bowl’s edge.
The accumulated solids in the disc centrifuge bowl are manually or self-expelled.
Imagine the liquid column being divided into thin slices by the centrifuge bowl’s discs separating it between the inter-disc spaces. Because of the viscosity of the incoming stationary (non-rotating) fluid, the rotating discs quickly transfer the rotational velocity to the liquid.
COST
Disc-stack centrifuge prices are influenced by a number of variables. The following is a ranking of the primary determinants of centrifuge cost.
Remanufactured, New, and Used
Most people start with brand-new centrifuges from the manufacturer, but these are frequently not financially feasible. A remanufactured centrifuge from the OEM or a reputable centrifuge company is the next available option. Finally, used “As-Is” centrifuges are a possibility as well, however they are not advised for safety reasons.
The starting price for a bare small-capacity disc centrifuge from a reputable OEM is approximately $15,000. Depending on the options, the same centrifuge with a skid, control system, wiring, alarms, etc. can cost more than $40,000. Conversely, centrifuges with a large capacity and food grade cost more than $750,000.
Remanufactured disc centrifuges have a 40% to 60% higher cost than newly constructed units with comparable capacity. A factory-new centrifuge’s cost increases more quickly with more options than a similarly equipped remanufactured centrifuge with new optional accessories.
The Throughput
The centrifuge’s processing capacity is indicated by its size. Naturally, larger, more powerful centrifuges are more expensive than smaller, less powerful ones. It is crucial to note, though, that the price of a larger centrifuge does not rise in direct proportion to its increased capacity. To put it another way, a centrifuge’s price does not always correspond to how much it can process.
For instance, the cost of a disc centrifuge rated at 10 gallons per minute is only roughly 30% higher than that of a centrifuge rated at 5 gallons per minute.
The Manufacturer
Disc centrifuges made by Asian manufacturers (China, India, Turkey, etc.) are less expensive than those made by well-known, established manufacturers like Alfa Laval or Westfalia (GEA). The multiplier for price can range from two to five times.
Alfa Laval industrial centrifuges are premium apparatuses renowned for their robustness and extended lifespan. These companies offer global service and parts distribution networks along with decades of manufacturing experience. The associated cost premium is more than justified by these benefits.
Choices & Add-ons
Disc centrifuges are frequently equipped with optional equipment to improve separator performance. The cost of the centrifuge system can be significantly increased by adding accessories like feed pumps, electric pre-heaters, pre- and post-filters, sludge handling systems, etc.
Options that would benefit the user are often defined by the actual conditions of the process and the properties of the process fluid. An in-line heater, for instance, will increase the cost of the system but has the potential to double centrifuge throughput.
Cost of Operations
The actual costs incurred when the centrifuge system is regularly operated are referred to as operating costs. Since centrifuges don’t require any replaceable media or filters, their only operational expense is the power to keep them running.
Power Usage
In a disc stack centrifuge, the drive motor is the major energy user. Industry standard procedure is to figure out how many kW are needed for every m3 or gallon of fluid processed.
Power consumption in centrifuges has decreased as a result of several design advancements. The design modifications have been especially helpful in a few particular areas.
Direct-drive configurations with inverters reduce drive train losses from gear and belt drive transmissions.
Optimizing power consumption has also benefited from improved designs that reduce internal bowl turbulence.
Disc Stack Centrifuge and Decanter Distinctions
The chamber bowl (disc-less) centrifuge’s rotating surface is the bowl wall as opposed to the disc-stack bowl. The inner fluid particles, which are away from the bowl wall, rotate considerably more slowly than the liquid particles that are in contact with the wall, depending on the depth of the fluid layer.
In chamber bowl centrifuges, the separation efficiency is significantly reduced by this decreased rotational velocity.
Similar restrictions apply to the liquid pond in the decanter centrifuge. The fluid next to the rotating bowl body comes into contact with it. The decanters’ ability to separate larger, denser particles is limited by this outer layer contact.
The decanter centrifuge’s particle separation range is greater than that of disc-stack centrifuges, in part because of this.
Additionally, the discs in the disc-stack centrifuge bowl expand the sedimentation area through settling. When taking into account the g-force and the surface area of the discs, the effective settling area in a disc-stack centrifuge is equivalent to several football fields!