A centrifuge is a type of research equipment that spins a liquid suspension at high rotational speeds to separate it into different layers according to density. Due to these high rotational speeds, centrifuges are delicate, can break easily, and can be dangerous when not used correctly. Following some simple operating guidelines should avoid injury during use.
Steps
Method 1 of 2: Prepare and Load the Samples
Step 1. Check centrifuge bottles and tubes for cracks before use
Because a centrifuge can spin at high speeds, a liquid sample can easily become an aerosol if not properly contained. Cracked tubes can break at high speeds or in the best case, liquid dripping onto the rotor.
Discard broken or cracked tubes to avoid accidental use in the future
Step 2. Cover the tubes with the appropriate cap
Tubes that have been specified for use in a centrifuge have a suitable plug or cap that seals them. Using a different lid or covering such as wrap or aluminum foil can easily cause spillage inside the centrifuge. Aerosolizing the sample can be dangerous to your health and the environment. Furthermore, it can lead to the loss of valuable samples.
Step 3. Clean the outside of the tube with disinfectant before placing it in the centrifuge
Cleaning the tube is especially important if you are working with biohazard material. You should limit any possible spillage or aerosol formation of the sample. The best prevention is to clean the sample with a suitable disinfectant before it begins to spin.
Step 4. Clearly identify the tubes
You may know how you put the tubes in the centrifuge before you start spinning, but in the end you won't be able to tell them apart. Make sure you put some kind of label on each tube so you know which sample is which.
It is better to label the tube directly rather than using a sticker. A decal can fall off during the turn making identification difficult
Step 5. Make a counterweight for the centrifuge tube that you want to put in the centrifuge
At high speeds, a centrifuge can easily become unbalanced if there are no equal masses opposite each other on the rotor. Remember to balance the masses of the tubes, not the volumes. Weigh the tube with the sample and record the mass. Add water to a separate empty tube until the mass is the same as the sample and label it as an equilibrium tube.
- Unbalanced tubes can lead to permanent damage to the centrifuge and can be dangerous if the rotor escapes from the rest of the centrifuge.
- Balance is extremely important at higher spin speeds.
- Many centrifuges will automatically shut off if they detect an unbalanced load, but older centrifuges may not have this feature. If the centrifuge begins to shake or shake, it is unbalanced and should be stopped immediately.
Method 2 of 2: Use the centrifuge
Step 1. Place the centrifuge on a firm, level surface
Due to the high speeds at which the centrifuge rotates, it must be placed on a solid, flat surface. Find a level table or counter that is safe and can adequately hold the weight of the centrifuge.
If you notice that the centrifuge is slipping or the counter is loose, return the centrifuge to a more stable location
Step 2. Choose the right rotor to use at the speed you need
The rotor is a part that spins the sample. Some rotors have arms that you can attach smaller cubes to, while other rotors are a piece that you put the tubes on directly. Rotors are designed for specific tubes and speeds. Use a rotor that fits the sample tubes and is within the required speed limit.
If the samples are in the wrong tube type, you may need to transfer them to a suitable type before they start to spin
Step 3. Load the tubes opposite each other into the centrifuge
If you are only spinning one sample, you will need to make a balance tube to load it directly in front of the sample tube. If you are spinning more than two tubes, only the ones that are directly opposite will need to be equal in mass.
Step 4. Enter the centrifuge speed
Centrifuge speed is generally given in rotations per minute (rpm), or how many times the rotor completes a full rotation in one minute. Speed can also be given in relative centrifugal force (RCF) or the G-force on the rotor. Modern centrifuges are digital and have settings for both.
The speed at which you spin the samples depends on what you are going to spin. Do your research online if you are not sure what speed to use
Step 5. Keep a safe distance while the centrifuge is leaking
Hitting or moving the centrifuge during use can cause imbalance and lead to injury. Larger centrifuges can spin at very high speeds and be extremely dangerous if unbalanced.
Step 6. Turn off the centrifuge if it wobbles
After turning the centrifuge on, stay nearby until it reaches full speed in case it needs to be turned off. When a centrifuge is out of balance, it may shake or wobble. This can damage equipment and can also lead to injury in the most serious cases. If you can't reach the power button, just unplug the centrifuge.
- Many centrifuges will automatically shut down if they detect an unbalanced load, but older centrifuges may not have this feature. If the centrifuge begins to shake or wobble, it is unbalanced and should be stopped immediately.
- A small amount of vibration is normal, but excessive wobbling is dangerous.
- If the samples are balanced and wobbling still occurs, stop using the centrifuge and call for maintenance.
Step 7. Open the lid only after the rotor has come to a complete stop
Many modern centrifuges have a lock that will not open until the rotor has stopped. Older centrifuges may not have this feature so make sure the rotor is no longer moving before opening the lid. Do not touch the rotors while they are in motion.
Keep power lines off the ground to avoid tripping hazards that could move the centrifuge
Step 8. Remove the tubes carefully after the centrifuge has completely stopped spinning
You should carefully remove the tubes so that the separate interruptions do not get mixed up again. You should also check if any of the samples have leaked or there are broken tubes.
If a spill occurs, clean the rotor and buckets immediately
Step 9. Clean the rotor and centrifuge after each use
To keep the centrifuge clean and running smoothly, lightly clean the rotor and centrifuge at the end of the spin. When you're done, leave the lid open so the air can escape and stay dry.
Advice
- Keep the lid closed while the centrifuge is spinning.
- When balancing the tubes, it is helpful to put a small container or similar object on the scale to keep the tubes upright so that you do not have to remove them from the scale to add water or other solvents..
- Always wear gloves.
Warnings
- Unbalanced centrifuges may move slowly across the surface they are on. Immediately turn off unbalanced centrifuges to avoid damage to the machine, yourself and those around you.
- Do not lean on the centrifuge or place objects in it while it is running.
- Do not put caps or other items in the centrifuge with the tubes.