Balancing of centrifugal fans in hospital air conditioners and office towers is the most accurate preventive maintenance process to eliminate noise and prevent premature failure of bearings and electric motors. At Khalili Engineer's Complex, by using on-site dynamic balance equipment, we identify and correct fan mass unbalance with micron precision without the need to fully open the system. Unlike traditional methods that only replace parts, our approach in industrial projects is to identify the source of vibration, which can be solved in more than 80% of cases by modifying the rotor mass and alignment.
Why is vibration critical in hospital ventilators?
In medical centers, fan noise is not only noise pollution, but also indicates a progressive mechanical wear and tear. Small vibrations over time cause the vanes to change shape and metal fatigue in the main shaft. According to our experience in implementing heavy projects in hospital centers, most ventilators suffer from "slack" or "low frequency vibration" due to the uneven distribution of mass on the centrifugal impellers.
When the fan vibration exceeds the standard, the vibration energy is transferred to the air ducts and amplifies the sound on the floors of the office towers. Engineer Khalili's solution here is balancing on the spot; That is, without moving the fan or long-term shutdowns, our portable balance device determines the exact points for weighting by measuring the phase angle and by adding calibrated weights, brings the vibration to the permissible range of the ISO 1940 standard.
The difference in field balance with part replacement
Many general service providers, their first suggestion is to change the impeller or bearing. But the technical reality is that even new parts may not be perfectly balanced at the factory. In our field experience, many noisy centrifugal fans require only a dynamic balancing operation to remove mechanical stress from the shaft.
While performing the service, we also check the condition of the entire power transmission system (belts and pulleys). Sometimes the source of the sound is not from the fan, but from the misalignment of the pulleys, which causes the engine to be under asymmetric pressure. Balancing the fan in such a situation, without correcting the alignment, is a fruitless task.
Specific challenges in local projects
In office and hospital tower projects that use high-flow centrifugal fans, the main challenge is the space limitation in the engine room. Our methods are designed in such a way that even in the limited spaces of modern engine houses, balancing operations can be performed without the need to destroy or completely disassemble the air conditioner. This means minimal disturbance in the cooling and heating system of the building during operation.