How and Why to Balance Your Centrifuge
A Balanced Centrifuge Runs Quieter, Lasts Longer and Performs Safely
A reliable bench-top centrifuge is essential to many veterinary tests, diagnoses and sample handling procedures. Balancing your laboratory centrifuge before each and every operation is the simplest and most effective action you can take to prolong its life, performance, reliability and safety.
How Your Centrifuge Works
Your laboratory centrifuge is an ultra-high-speed electric motor driving a vertical spindle which spins the rotor. The rotor is basically a means of safely holding various laboratory samples. When the rotor spins, it effectively creates an outward force (called the g-force) thousands of times that of Earth’s gravity within the samples.
The g-forces created by centrifugation greatly magnify tiny weight differences within the spinning samples, greatly reducing the time taken for more dense material – such as solid matter, to separate out from the less dense material – such as water. Material that would take days to ‘settle out’ on the laboratory bench can be ‘centrifuged down’ in a few minutes.
Why Balancing Your Laboratory Centrifuge Matters
However, these same g-forces also magnify any slight differences in the uneven distribution of weight around the rotor. Even a slight weight imbalance between samples will cause the centrifuge to vibrate, shake uncontrollably and, in extreme circumstances, even explode.
Running a high-speed centrifuge with an unevenly loaded rotor is the most common cause of centrifuges breaking down. Out of balance loading causes the moving parts to shake uncontrollably. At best, this means the motor and bearings wear out more quickly. At worst, it risks sudden and explosive failure of the motor or rotor, and serious injury to laboratory personnel.
How to Balance Your Centrifuge
Balancing your centrifuge is as simple as it is critical. It’s just a matter of evenly distributing the weight of your lab samples around the rotor before switching on. In practice, it means that for each sample placed in the centrifuge, a sample of exactly the same weight must be placed on the exact opposite side of the rotor, as if joined by a line directly through the centre of the rotor.
Always operate your centrifuge using an even number of equally filled sample tubes of the same size and material distributed symmetrically across the centre of the rotor. If you find yourself with only one sample to spin down, always make yourself a ‘balance’ sample of the same size and weight to keep the rotor evenly and symmetrically loaded.
Seven Simple Rules for Balancing Your Laboratory Centrifuge
Whether you’re centrifuging haematocrit tubes, blood sample tubes, Eppendorf tubes, universal containers or commercial diagnostics such as Ovatube tubes, here are seven simple rules to prolong the life, performance, reliability and safety of your veterinary centrifuge.
Click on the PDF below for a visual guide on how to balance your centrifuge
- Always follow the manufacturer's instruction for operating your centrifuge
- Always use the centrifuge rotor specifically designed for samples to be centrifuged
- Always ensure the rotor is securely fixed – if in doubt, have it checked
- Always load your centrifuge with one type of sample tube or container only
- Always centrifuge samples of the equal weight – check their weights before loading
- Always balance each sample with its equal on a line through the centre of the rotor
- Always keep the inside of your centrifuge clean and dry and free of debris