Kaeser Kompressoren (German OEM) uses centrifugal impellers in their "Sigma Air" series of turbo compressors, as well as older DSD, ESD, or SFC models.
Unlike screw elements, centrifugal impellers are speed-rated, balanced, and coated specifically to one compressor's serial number.
Critical Identification (Do not order without this)
To find the correct impeller, you need three exact data points from your unit's nameplate:
Machine Type: (e.g., DSD 241, ESD 341, SFC 35, Sigma Air 36-45)
Serial Number (S/N): (e.g., 123456) – Crucial for stage 1 vs. stage 2
Impeller Stage: (Low-pressure / High-pressure)
Where to Source
Source | Part Number Availability | Typical Lead Time | Cost Estimate (New) |
Requires OEM drawing | 2-4 weeks | 40%-60% of New OEM | |
Kaeser Direct | Exact OEM match, includes balancing | 4-8 weeks | $6,000 - $15,000+ |
Kaeser Certified Rebuild | Exchange program (send old, get reman) | 2-4 weeks | $3,500 - $8,000 |
Aftermarket | Requires OEM drawing | 6-10 weeks | $2,500 - $6,000 |
Used / Surplus | Hit-or-miss; risk of imbalance | Variable | $800 - $2,500 |
Critical Technical Warnings
Do not install a bare impeller. A centrifugal impeller for a Kaeser must be:
High-speed balanced (ISO 1940 G1.0 or better, often VSR). Field balancing is impossible.
Dimensionally matched to your specific shaft taper (not all Kaeser M-Series fit all).
Coated correctly (anti-corrosion/anti-fouling like Ni-PTFE or aluminum anodizing).
Paired with new labyrinth seals – if the impeller touched the housing, the seals are gone.
Most Common Failure Causes (to prevent repeat failure)
Ingress of liquid (water condensation during shutdown)
Filter bypass (failed air intake filter element)
Foreign object (scale, weld slag, desiccant dust)
Overspeed / surge event
Immediate Next Step
Contact us with your S/N and ask:
*"I need a replacement centrifugal impeller for stage [1/2] of model [XXX], serial [XXXXX]. Please confirm OEM part number and whether an exchange unit is in stock."*
If the unit is down and you are in the Asia or other place of world, also Email us Compressor Parts International (CPI) at market@cd-steel.com – they reverse-engineer Kaeser centrifugal impellers.
Provide your compressor's model and S/N, and I can look up the likely OEM part number range.
