The centrifugal impeller is the most critical rotating component in a Kobelco centrifugal air compressor. It accelerates air radially outward via high-speed rotation, converting velocity energy into pressure energy in the diffuser and volute.
For Kobelco models (e.g., KOBELCO KOBE STEEL series like TA-, TM-, TRE-, or M-series for air compressors), the impeller is typically:
Material: High-strength aluminum alloy (e.g., 7075-T6) or stainless steel (e.g., 17-4PH), depending on model and operating pressure.
Manufacturing: Precision 5‑axis CNC machined or forged, with full static & dynamic balancing (ISO 1940 G1.0 or better).
Features: Open or closed type? Kobelco often uses closed (shrouded) impellers for higher efficiency and reliability in oil‑free air applications.
Key considerations for replacement or sourcing:
OEM vs. aftermarket
OEM (Kobelco) guarantees exact fit, material certs, and balancing. Expensive but low risk.
Aftermarket (e.g., Compressor Parts International, Bala Sura, or Turbo-Tek) can be 30–50% cheaper but must match:
Original part number (etched on hub)
Eye diameter, exducer diameter, blade count, and hub profile
Balance grade and overspeed test data
Critical specs needed for ordering
Compressor model & serial number (e.g., TRE-90E, TA-80).
Impeller drawing or OEM part # (e.g., KBE-xxxx).
Design speed (rpm) and airflow range (m³/min or cfm).
Common failure signs
Decreased flow/pressure, vibration increase, or metallic noise.
Caused by foreign object damage (FOD), fatigue cracks, or corrosion in humid environments.
Installation notes
Must be reinstalled with new locknut, key, and torque per Kobelco manual.
Re-balancing with the shaft assembly (if required) is mandatory.
Check axial clearance (typically 0.2–0.4 mm) and labyrinth seal condition.
