The Correct Installation Procedure for Laboratory Centrifuges

The centrifuge is one of the commonly used laboratory instruments. The installation of a centrifuge plays a crucial role in determining its service life. Today, our editor has summarized for you the key points to consider when installing laboratory centrifuges.

1. Correct installation

(1) Power supply voltage: Voltage fluctuations must comply with the national standard within a tolerance of 10%. Otherwise, centrifuges from certain manufacturers may fail to operate properly. If voltage fluctuations exceed this tolerance, it is recommended to use a voltage stabilizer to ensure compliance with the power grid requirements.

(2) The grounding wire must be secure: The wiring of the room’s power supply must meet the required standards. In China, the power system uses a three-phase four-wire configuration. The three phases refer to the three phases used in industrial electricity; when using three-phase power, the neutral wire and the ground wire must be kept separate. More importantly, whether it’s three-phase industrial power or ordinary single-phase power, the ground wire must be reliably connected to prevent electric leakage. Under no circumstances should the ground wire be connected to hot water pipes or water supply pipes.

(3) The floor must be level and stable: For large centrifuges, the floor at the installation site must be sturdy and well-secured to ensure the rotor operates smoothly without sinking or sagging. The floor at the installation and fixing location should be both level and stable.

(4) Adjust the level: Use a small, relatively accurate spirit level. With the centrifuge lid open, check for level on the main shaft. Adjust the level by turning the adjusting bolts located next to the four casters. Be sure to pay attention to ensure that none of the four feet is unsupported.

2. Load the sample and find balance.

During the design and manufacturing of centrifuges, any imbalance caused by machining errors in the rotor has been corrected through dynamic balancing tests. However, all centrifuges have a permissible level of sample loading imbalance.

To compete with other manufacturers on the maximum allowable imbalance limit for centrifuges, centrifuge manufacturers tend to specify the highest possible value. At this higher limit, the centrifuge can still operate—but the resulting unbalanced forces will suddenly impact the bearings and support structures at a frequency of n times per minute, causing damage to the centrifuge. Therefore, for those expensive centrifuges, users should strive to achieve optimal balance before starting the centrifuge; doing so will significantly extend the equipment’s service life.

3. Remove any accumulated water from the centrifuge chamber.

When the centrifuge is running, refrigeration causes moisture in the air to condense into frost inside the centrifuge chamber. After the machine is turned off, this frost melts into water. Most low-speed, high-capacity centrifuges from overseas do not have drain holes, so water gradually accumulates in the centrifuge chamber. In such cases, users should remove the rotor themselves and clear out the accumulated water. When reinstalling the rotor, be sure to secure it properly to prevent accidents.

4. Aluminum alloys must not be subject to corrosion.

Centrifuge rotors are typically made of aluminum alloy. Once corroded, their strength is reduced, making them prone to accidents. Aluminum alloys are susceptible to liquid corrosion; after cleaning, be sure to dry them thoroughly using a hairdryer or by inverting them for a while until they are completely dry before use. Some blood banks’ imported centrifuges lack the six plastic holders that should normally be included in the six aluminum cups. These plastic holders are meant to hold blood bags, preventing them from being placed directly into the aluminum cups. Also, pay close attention to whether the test tubes have any cracks. If a test tube—especially one that has been used repeatedly—shows even the slightest crack, never use it under any circumstances. Otherwise, during operation, a cracked test tube could cause an imbalance during rotor rotation, potentially leading to serious accidents such as shaft breakage.

5. Shaft Breakage Accident

The rotor was not properly installed, or the sample loading was severely unbalanced. When the centrifuge is started, modern imported centrifuges are equipped with imbalance protection: if the imbalance exceeds a certain threshold, the machine will automatically cut power and stop rotating. However, in the situation described above, it’s already too late—such a scenario could lead to a serious accident. One type of severe accident is shaft failure. When the shaft suddenly breaks during high-speed rotation, the centrifuge rotor loses its support and starts spinning wildly within the chamber, potentially causing the entire centrifuge to rotate by as much as 270 degrees. At this point, if there happen to be personnel or equipment nearby, it could result in injuries or fatalities among staff and damage to equipment.

(Source: Internet)