Teaching you about the installation and maintenance of Shanghai centrifuges.

1.1 Correct Installation

(1) Power supply voltage: Voltage fluctuations must comply with the national standard within ±10%; otherwise, centrifuges from certain manufacturers may fail to operate properly. If voltage fluctuations exceed this range, 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-phase electricity used in industrial settings. 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 standard single-phase power, the ground wire must be reliably connected to prevent electric leakage. Under no circumstances should the ground wire be connected to heating pipes or water pipes.

(3) The floor must be level and stable: For large centrifuges, the floor at the installation site must be firmly secured to ensure that the centrifuge rotor operates normally without sinking or becoming uneven. The floor surface at the installation and fixing locations should be both level and sturdy.

(4) Adjust the level: Find a small, relatively accurate spirit level. With the centrifuge lid open, locate the horizontal position on the main shaft. Adjust the level by turning the adjusting bolts located next to the four casters. Be sure to pay attention that one of the feet must not be unsupported.

1.2 Load the sample and find balance

During the design and manufacturing of centrifuges, any imbalance caused by machining errors in the rotor is corrected through dynamic balancing tests. However, every centrifuge has a permissible level of sample loading imbalance. To compete with other manufacturers on the metric of maximum allowable imbalance, centrifuge manufacturers tend to specify the highest possible value within this limit.

At this higher value, the centrifuge can still operate; however, the resulting unbalanced forces will suddenly impact the bearings and support structure at a frequency of n times per minute, causing damage to the centrifuge. Therefore, for those expensive centrifuges, users should strive to achieve proper balance before starting the centrifugation process—this will significantly extend the lifespan of the centrifuge.
 
1.3 Remove 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 reassembling the rotor, be sure to install it correctly to prevent accidents.

1.4 Aluminum alloys must not be subject to corrosion.

Centrifuge rotors are typically made of aluminum alloy. Once corroded, their strength diminishes, making them prone to accidents. Aluminum alloys are susceptible to liquid corrosion; after cleaning, they should be dried thoroughly using a hairdryer or by turning them upside down for a period of time to ensure they’re 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 test tubes have any cracks. If a test tube—especially one that has been used repeatedly—shows even the slightest crack, it must never be used. Otherwise, during operation, a cracked test tube could cause an imbalance during rotor rotation, potentially leading to serious accidents such as shaft breakage.

1.5 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 an imbalance 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 are people or equipment nearby, it could result in injuries and damage to both personnel and equipment.