FAQ about Centrifuges2013-07-03
Liquid-solid separation is a process where suspended solids are separated from a liquid media.
Centrifugation is a highly accelerated form of sedimentation. Centrifuge Systems machines generate 4,000 times gravity of centrifugal power for greater liquid-solid separation. This method is fast and eliminates the need for filter media. Centrifuge Systems has a complete range of liquid-solid separation centrifuges designed to separate suspended solids heavier than liquid media without the use of consumable filters.
Sedimentation allows solid particles heavier than the liquid media to separate and sink to the bottom of a container under the force of gravity. Sedimentation is a relatively slow process.
Filtration incorporates the use of a filter media to regulate what may pass through. As the filter media collects suspended solids, a progressive build-up of the solids will eventually impair performance and require removal, cleaning and perhaps replacement.
How does a Centrifuge Work?
Centrifuges work by spinning a vessel at high speeds to create separation between materials inside the centrifuge operation. Centrifuges spin at high speeds to push material, usually of solid state, away from the center of the vessel and out of the liquid state.
For example, the same science applies to rides at the fairgrounds that rotate with passengers buckled in. Passengers must lean toward the center to overcome the gravitational force caused by the rotation. Some rides are designed to press the passenger against a back support. In the same fashion, centrifuges push the material away from the center of the bowl hub to the outer walls of the bowl.
What Is The Centrifuge Process?
When a sample of a liquid-solid mixture is collected in a flask, it will eventually result in a two-phase separation caused by gravitational force. This is sedimentation. Centrifuges accelerate the process by increasing the force to as high as 4,000 times gravity; therefore, a process that takes 1-12 hours in a flask is achieved within seconds of a centrifuge.
How Do I Know What Type Of Centrifuge To Choose?
Solutions engineers will help you. The type of centrifuge depends on (A) type and volume of solids produced by the separation and (B) g-force required to make separation. At DC Centrifuge Systems, customers are guided through this individualized process with expert help from DC machinery to make any centrifuge you want.
How Do I Choose a Centrifuge?
Solutions engineers focus on finding the best solutions for customers and determine the centrifuge system that best suits the industrial application. Large variety of both standard and unique applications makes choosing the correct centrifuge an artful science.
Determining the correct machine design and model size requires thorough understanding of the application, better understood with application sample testing run by DC Centrifuge Systems.
To design a centrifuge system, Solutions Engineers considers the following information:
1. Liquid and solid phase description
2. Total liquid volume of the system
3. Process time amount, availability and any required process flow rates
4. Quality of required liquid phases
5.Targeted concentration of impurities
6.Targeted dryness of solids
7. Amount of solid removal from given liquid volume
8. Goals to achieve
Simple calculations can quickly determine what style of liquid-liquid and liquid-solid centrifuge separation technology, solids dewatering, and centrifuge liquid filtration and fluid clarification is best for the application. Additional centrifuge tests determine the most appropriate type of centrifuge systems, whether it fits the goals to achieve, budget, time and scope of supply.
What Are The Applications For A Centrifuge?
Common industrial applications include:
1. Solid separations that are heavier than the liquid and settle with time
2. Solid classifications of different size in a slurry
3. Immiscible liquid separation with different densities
4. Common concepts applied to specific process requirements:
5. Dewatering a solid
6. Clarification of liquid
7. Recovery of product
8.Thickening of slurry
9. Classification of slurry
Industries and processes that often utilize centrifuges include:
4. Chemical and Pharmaceutical
5. Carwash wastewater
6. Drilling Fluid
9. Food and Beverage
11. Glass gGrinding
13. Industrial Laundry Wastewater
16. Machine Coolants
18. Metal Finishing
19. Plastic Finishing
20. Mineral Oil
21. Oil Remediation
22. Paint Sludge
24. Plastic Recycling Wash Water
26. Potato Waste
27. Screen Print Solvents
28. Sludge Dewatering
30. Stone Fabrication
32. Vibration / Mass Finishing
34. Waste Oils
35. Wire Drawing Lubricants
What Are The Advantages Of Using A Centrifuge Over Other Methods?
Centrifuges often offer numerous advantages over traditional methods of liquid-liquid and liquid-solid centrifuge separation technology, solids dewatering, and centrifuge liquid filtration and fluid clarification. While specific advantages depend on the nature of the application, common benefits include:
1. No consumable filter media or pre-coat is required
2. Chemical addition is not always a requirement
3. Will not blind-off or clog-up
4. Maintains full system flow rates
5. Automatic continuous and semi batch self-cleaning centrifuges available
6. No human contact with the waste material, which can be discharged directly into a waste drum, hopper, bin, or roll-off container
7. 2-micron-sized suspended solids after separation
8. Relatively moisture-free cake created for disposal or reclaiming
9. Effective on low solid volume applications
What are the Alternatives to a Centrifuge, and Why is Using a Centrifuge Better Than These Alternatives?
Common centrifuge alternatives:
1. Filter Press
2. Belt Filter Press
3. Bag Filter
4. Membrane Filter
Centrifuges are considered an effective alternative to the filter press. Centrifuge design features an automated self-cleaning cycle that does not require constant labor and maintenance to maintain operation.
Centrifuges are also considered a more economical and effective alternative to the belt filter press. Centrifuges are often less expensive to purchase. Centrifuges require less labor and maintenance, and unlike a belt filter press, can provide suitable results without polymer addition in specific applications.
Bag filter systems are cheaper, but the centrifuge still does not require consumable filter bags or the manual handling of sloppy wet filter bags. Centrifuges will not clog and blind off when filtering gelatinous materials from the liquid media. Automated self-cleaning centrifuges separate sludge cake and discharge the cake directly into a waste drum or hopper for disposal with no direct human-sludge contact.
When combined with a membrane filtration system, a centrifuge is a helpful addition as a pre-filter. Centrifuges can be applied to the membrane concentrate. Fouling of the membrane flux rate can be maintained over a longer period of time with the centrifugation of the liquid media and separation of a large percentage of the small particles.