The Basics of Centrifuge Operation and Maintenance (2023)

Part 1: What is a centrifuge used for?

Centrifuges are used in various laboratories to separate fluids, gases, or liquids based on density. In research and clinical laboratories, centrifuges are often used for cell, organelle, virus, protein, and nucleic acid purification.

An example of centrifuge use in a clinical setting is for the separation of whole blood components. Different assays necessitate serum or plasma, which may be obtained with centrifugation.

Serum is obtained by letting a whole blood sample clot at room temperature. The sample is then centrifuged and the clot is removed, leaving a serum supernatant.

Unlike serum, plasma is obtained from whole blood that is not left to clot, and contains serum along with clotting factors. To obtain plasma, a whole blood sample is collected in tubes treated with anticoagulants. Following centrifugation, cells are removed and plasma supernatant remains.

The Basics of Centrifuge Operation and Maintenance (1)

Part 2: How does centrifugation work?

Principles of centrifugation

A centrifuge is used to separate particles suspended in a liquid according to particle size and density, viscosity of the medium, and rotor speed.

Within a solution, gravitational force will cause particles of higher density than the solvent to sink, and those less dense than the solvent to float to the top. Centrifugation takes advantage of even minute differences in density to separate particles within a solution.

(Video) The Basis for Your Lab Safety - Centrifuge Training and Maintenance

As the rotor spins around a central axis, it generates a centrifugal force acting to move particles away from the axis of rotation. If the centrifugal force exceeds the buoyant forces of liquid media and the frictional force created by the particle, the particles will sediment.

The Basics of Centrifuge Operation and Maintenance (2)

Centrifuge Rotor Types

There are two very common rotor designs: fixed angle, and swinging bucket. The fixed angle rotor is designed to hold tubes in a fixed position at a fixed angle relative to the vertical axis of rotation (up to about 45°). Centrifugation will cause particles to sediment along the side and bottom of the tube. The swinging bucket design allows the tubes to swing out from a vertical resting position to become parallel to the horizontal during centrifugation. As a result, sediment will form along the bottom of the tube.

Fixed angle rotors are ideal for pelleting applications either to remove particles from a suspension and discard the debris or to recover the pellet, whereas swinging bucket rotors are best for separating large volume samples at low speeds and resolving samples in rate-zonal (density) gradients.

The Basics of Centrifuge Operation and Maintenance (3)

Part 3: How do you choose a centrifuge?

Centrifuge speed

The Basics of Centrifuge Operation and Maintenance (4)

Centrifuges may be classified based on maximum speeds, measured as revolutions per minute (RPM). Speeds range from 0-7,500 RPM for low-speed centrifuges, all the way to 20,000 RPM or higher.

(Video) How to Use a Centrifuge

Centrifuge rotor speed is often expressed as RCF in units of gravity (x g) for various procedures. However, many centrifuges display speed as revolutions per minute (RPM), necessitating conversion to ensure the correct experimental conditions. The following formula is used to convert RPM to RCF, where R is the rotor radius (cm) and S is the speed (RPM):

g = (1.118 x 10-5) R S2

Centrifuge size

The Basics of Centrifuge Operation and Maintenance (5)

Centrifuges are available as various benchtop or floor-standing models.

Floor-standing models offer greater sample capacity and can achieve high speeds. Superspeed centrifuges can achieve a maximum g-force (relative centrifugal force, RCF) of over 70,000 x g, and ultracentrifuges often used for DNA or RNA fractionation, can achieve up to 1,000,000 x g.For large-capacity, low-speed applications, low-speed centrifuges reaching approximately 7000 x g are available.

Benchtop models have a smaller footprint, and general-purpose models are ideal for a wide range of applications. There are many benchtop models available, including high-speed, microcentrifuge, clinical, and cell washer models. Clinical benchtop models and cell washers typically operate at lower speeds, and are suited to diagnostic applications, and washing debris from red blood cells.

Centrifuges for different applications

It is essential to select a centrifuge that is suited to the specific application. When purchasing a centrifuge, it is important to consider the following questions:

(Video) Clinical Centrifuge servicing tutorial

  • What sample volumes are you working with? For processes involving large or varying volumes, a floor-standing model with higher capacity and different rotor configurations may be the best solution.
  • Are samples temperature sensitive? If so, a centrifuge with refrigeration and temperature control options is required.
  • Will the centrifuge be used for processing clinical or blood banking samples? Cell washers or clinical models are available for these specific applications.
  • How much laboratory space is available vs the centrifuge footprint?
  • What is the maximum g-force the centrifuge is capable of generating? Low-speed centrifuges are ideal for separating whole cells, while ultracentrifuges are necessary for separating DNA and RNA.

Part 4: What safety precautions should be taken when working with a centrifuge?

Ensure a sturdy, level worksurface

Always ensure the centrifuge is on an appropriate surface prior to operation.

Balance the centrifuge

Running an unbalanced centrifuge may cause significant damage, and injure the operator and other laboratory personnel. The total mass of each tube should be as close as possible- this becomes increasingly important at very high rotor speeds. Balancing masses to the nearest 0.1 gram is advisable, and it is important to balance tubes by mass, not volume. For example, do not balance a sample consisting of liquid with a higher or lower density than water with an equal volume of water.

Do not open the lid while the rotor is moving

Many centrifuges have a “safety shutoff.” However, this will only stop power to the rotor, which will still spin due to its own inertia for some time until it is slowed to a stop by friction.

If the centrifuge is wobbling or shaking, pull the plug

A little vibration is normal, but excessive amounts can mean danger. First, double check that the tubes are correctly balanced. If this does not resolve the issue, do not operate the centrifuge until it has been serviced by the manufacturer or dealer.

Part 5: How do you balance a centrifuge?

Why you need to balance a centrifuge

Prior to starting the centrifuge, it is necessary to load it correctly. Balancing the centrifuge prevents potential damage to the instrument, and is crucial for safe operation.

How to balance a centrifuge

  1. Ensure all sample tubes are evenly filled. If additional tubes are required for balancing, fill them with water or a liquid of similar density to the sample, and ensure the mass is balanced to the nearest 0.1 grams.
  2. For each tube inserted in the rotor, add a tube of equal weight directly opposite it. This will ensure the center of gravity remains in the center of the rotor.
  3. Rotate the rotor 90° and add two additional tubes directly opposite one another.
  4. Repeat.

The Basics of Centrifuge Operation and Maintenance (6)

How to balance 3 tubes, 5 tubes, or 7 tubes in a centrifuge with 12 positions

There are two ways to balance three tubes. The first option is to insert three sample tubes next to each other, and create three balance tubes to be situated directly across from the sample tubes.

(Video) Better Safe than Sorry! Safety & Maintenance for Benchtop Centrifuges

Alternatively, three sample tubes may be spaced evenly around the rotor.

The Basics of Centrifuge Operation and Maintenance (7)

To balance five tubes, create one balance tube and place two sets of three tubes across from each other.

The Basics of Centrifuge Operation and Maintenance (8)

To balance seven tubes, create one balance tube and place two sets of four tubes across from each other.

The Basics of Centrifuge Operation and Maintenance (9)

Part 6: How do you maintain a centrifuge?

Centrifuge care and maintenance

A few simple steps can keep a centrifuge functioning properly and reduce the risk of damage or injury.

(Video) 642E Basic Operations Guide

  • Keep the centrifuge properly lubricated. O-rings are the main source of protection against sample leakage, and must be lubricated prior to installation of a new rotor or following cleaning. Any threaded components should also be cleaned regularly and lubricated with an approved grease to ensure proper operation and to prevent cross-threading and corrosion.
  • Ensure all users are aware of how to properly operate the centrifuge, including ensuring buckets are properly seated in their pins, balancing tubes in the rotor, operating rotors within stated guidelines for speed and maximum compartment mass, and avoiding scratching the rotor.
  • Inspect critical components, and look for signs of wear including scratches, or effects of chemical exposure on the rotor.
  • Pay close attention to noise, vibration, shaking, or grinding and stop the unit immediately if this occurs.

Centrifuge cleaning

Regularly clean the centrifuge with neutral cleaning solutions (alcohol or alcohol-based disinfectant) applied with a soft cloth to rotors and accessories. Daily cleaning should include the interior portion of the centrifuge, the rotor chamber, and surfaces with electronic components, such as touchscreens and keypads.

It is important to be aware of the different types of samples used with the centrifuge and any specific products or protocols necessary for cleaning spills.

Additional resources:

  • What to Ask When Buying a Centrifuge, and Other Helpful Tips
  • Centrifuges Product Page


What are the maintenance procedures on a centrifuge? ›

Clean your centrifuge daily

A plastic scrub brush should be used to avoid damaging the coatings. When finished with the cleaning, you should use a centrifuge lubricant to lubricate the bucket grooves and rubber seals. Check for residue and corrosion on the rotors on a weekly or monthly basis.

What is the operation of a centrifuge machine? ›

A centrifuge spins samples at a high speed, the centrifugal force causes denser materials to travel to the bottom of the centrifuge tube rapidly. This allows for the separation of liquid and solid samples.

What is the basic principles of centrifugation? ›

What is the principle of centrifugation? A centrifuge operates by using the sedimentation principle- Here the substances are separated based on their density under the influence of gravitational force.

What are the basic components of centrifuge? ›

There are two basic components to all centrifuges, the rotor assembly, and the electrical motor. The rotor assembly is that part of the centrifuge that transfers the rotation motion produced by the electrical motor.

What is one of the most important rules when using a centrifuge? ›

Do not bump, jar, or move the centrifuge while the rotor is spinning. Instruct all other persons in the area to stay clear of the unit while it's operating. Make sure you don't have the cord dangling from a table edge where someone could catch their foot in it and pull down the centrifuge.

What are the three types of centrifuge? ›

Three types of centrifuge rotor. Centrifuge rotors fall into three categories: swinging-bucket rotors, fixed-angle rotors, and vertical rotors.

What are the two types of centrifuge? ›

Generally, there are two types of centrifuge— micro centrifuge and tabletop centrifuge. These two differ on the sample capacity and types of rotor used, but both are used for sample separation by subjecting the samples in a containing vessel at a high-speed rotation.

How does a 3 phase centrifuge works? ›

Working Principle

The screw conveyor rotates within the bowl at a differential speed to the bowl. The relative rotation between the bowl and the screw pushed the solids to the bowl's conical section. The centrifugal force drains the liquid from the solids as they move up the conical bowl wall.

What are 3 applications of centrifugation? ›

The extraction of fat from milk in order to produce skimmed milk. The removal of water from moist lettuce with the help of a salad spinner. The Spin-drying of water in washing machines in order to remove water from the clothing. The separation of solid blood and urine materials into forensic and testing laboratories.

What are the parts of centrifuge and its function? ›

Parts of Centrifuge
  • Motor: Electric motor is a part of the centrifuge which helps to drive.
  • Control Panel: The control panel placed on the front casing serves the purpose of controlling centrifuge operation.
  • Chamber: The entire system is housed within a chamber.

What is the most important part of loading a centrifuge? ›

Whenever you load the centrifuge, you need to be careful to keep the rotor balanced. Every tube must be balanced by a tube of approximately equal weight on the opposite side of the rotor. At the maximum speed setting, the centrifuge creates a force of 8,000 G at the bottom of the tube.

How many type of centrifuge procedures is there? ›

Centrifugation Techniques

There are two types of centrifugal techniques for separating particles: differential centrifugation and density gradient centrifugation. Density gradient centrifugation can further be divided into rate-zonal and isopycnic centrifugation.

What PPE is required when operating a centrifuge? ›

Wear appropriate PPE: Including safety eyewear, gloves, a lab coat, and appropriate street clothing (i.e., long pants and closed-toe shoes). Ensure gloves are compatible with hazard(s). Inspect centrifuge: Ensure tubes are rated for intended use (speed, temperature, and chemical resistance)

What is the weekly maintenance of centrifuge? ›

Weekly to monthly:

Carefully remove rotor from centrifuge. Make a detailed inspection of the centrifuge rotor, rotor lid, and buckets for cracks and corrosion. For a fixed-angle rotor, check underneath the rotor as well as the tube bores. For a swing-bucket rotor, pay special attention to the pivots and grooves.

What is equipment maintenance procedure? ›

Equipment maintenance involves using maintenance methods and procedures to keep organizational equipment in good working condition. It includes both regular inspections and corrective repairs of assets.

What are three safety rules that must be followed when using a centrifuge? ›

Follow these steps for the safe operation of centrifuges: Ensure that centrifuge bowls and tubes are dry. Ensure that the spindle is clean. Use matched sets of tubes, buckets and other equipment.


1. 614B Basic Operations Guide
(Drucker Diagnostics)
2. centrifuge operation
(Anne Leidigh)
3. Centrifuge
4. Video 2021-12-01 Operation of Centrifuge TD4
(Jiang William)
5. Oil Centrifuge Care and Maintenance by
(Pa Biodiesel Supply)
6. Centrifugal Pump Basics - How centrifugal pumps work working principle hvacr
(The Engineering Mindset)
Top Articles
Latest Posts
Article information

Author: Jamar Nader

Last Updated: 12/26/2022

Views: 6167

Rating: 4.4 / 5 (75 voted)

Reviews: 82% of readers found this page helpful

Author information

Name: Jamar Nader

Birthday: 1995-02-28

Address: Apt. 536 6162 Reichel Greens, Port Zackaryside, CT 22682-9804

Phone: +9958384818317

Job: IT Representative

Hobby: Scrapbooking, Hiking, Hunting, Kite flying, Blacksmithing, Video gaming, Foraging

Introduction: My name is Jamar Nader, I am a fine, shiny, colorful, bright, nice, perfect, curious person who loves writing and wants to share my knowledge and understanding with you.