In a ventilation system, the fan blade (impeller) is the critical aerodynamic component that converts rotational torque into airflow. Over time, blades can suffer from material fatigue, stress corrosion cracking, or physical impact damage. A compromised blade is a safety hazard that causes extreme vibration, leading to the "death" of the motor and bearings.
As part of a Mechanical Fan Overhaul, EKG provides precision fan blade replacement, ensuring the new impeller is perfectly matched to the motor’s performance curve and the building's static pressure requirements.
We perform a "Structural Integrity Audit" to determine if a blade can be repaired or must be replaced:
Stress Fractures: Hairline cracks, usually near the "hub" or "root" of the blade, caused by years of centrifugal force and start-stop cycles.
Leading-Edge Erosion: In exhaust or high-velocity systems, the edges of the blades "thin out" due to particulate impact, losing their aerodynamic lift.
Irreversible Deformation: If a fan has "thrown a belt" or ingested a foreign object, the blades may be bent. Attempting to "bend them back" weakens the metal and creates a permanent unbalance.
Catastrophic Pitting: Deep corrosion that has compromised more than 10% of the metal thickness, making the blade unsafe at high RPMs.
Replacing a fan blade isn't just about "bolting on a new one." It requires precise mechanical synchronization:
Aerodynamic Matching: We ensure the new impeller has the exact same Pitch, Diameter, and Blade Count as the original. Upgrading to a modern "Airfoil" or "Backward-Curved" design can often increase efficiency by 15%.
Taper-Lock Integration: We utilize high-precision Taper-Lock bushings to fuse the new impeller to the shaft. This eliminates "Shaft Wobble" and makes future maintenance easier.
Dynamic Balancing (ISO G2.5): A new blade is never perfectly balanced out of the box. We perform In-Situ Dynamic Balancing once installed to ensure the vibration levels are below 2.0 mm/s.
Material Selection: Depending on the environment, we provide replacements in G90 Galvanized Steel, 316 Stainless Steel, or Reinforced Polyamide (Plastic) for chemical resistance.
A new, clean fan blade moves air more efficiently than a worn or dirty one. By restoring the "Laminar Flow" over the blade surface, the motor does less work to move the same volume of air.
Efficiency Recovery: A new impeller can reduce the "Brake Horsepower" (BHP) required by the system.
The Math: This efficiency allows your Variable Frequency Drive (VFD) to maintain the building setpoint at a lower frequency. According to the Cube Law, a 20% reduction in fan speed results in a nearly 50% reduction in power consumption.
| Feature | Standard "Patch" Job | EKG Mechanical Overhaul |
| Blade Quality | Generic / Non-Certified | OEM or Upgraded Airfoil Profile |
| Hub Connection | Set Screws (Prone to slipping) | Taper-Lock / Keyway Machining |
| Balancing | Static (Single plane) | Digital Dynamic (Dual-plane) |
| Fasteners | Standard Grade 5 | High-Tensile Grade 8.8 / Nord-Lock |
| Verification | Visual Check | Vibration Spectrum & CFM Report |
BOMBA & Safety Compliance: For smoke-spill or fire-safety fans, we provide certified replacement blades that meet high-temperature (e.g., 250°C for 2 hours) fire ratings.
Laser Alignment: After installing the new impeller, we perform a Laser Shaft Alignment to ensure the weight of the new blade isn't creating a "Side-Load" on the motor bearings.
Performance Curves: We don't guess. We map the new blade against your fan’s original Pressure vs. Flow (P-Q) curve to ensure your building’s air balance isn't disrupted.
Rapid Fabrication: For obsolete fans, we can "Reverse Engineer" and CNC-fabricate custom impellers to match your existing housing, saving you the cost of a full unit replacement.
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