A, B and C Trimmed Impellers: Matching a Pipeline Pump to the Duty
A pump bought with far more head than the system needs wastes energy for its whole life, or is throttled back with a valve. Trimmed impellers are the cheaper fix: the same casing with a slightly smaller impeller.
The 40-250(I) family
| Build | Flow (m³/h) | Head (m) | Motor (kW) |
|---|---|---|---|
| 40-250(I) | 12.5 | 80 | 11 |
| 40-250(I)A | 11.6 | 70 | 7.5 |
| 40-250(I)B | 10.8 | 60 | 7.5 |
| 40-250(I)C | 10 | 52 | 5.5 |
From the full impeller to the C trim, the head drops by about a third and the motor by half, in the same frame and with the same flanges.
How to choose
- Work out the head the system really needs at the design flow.
- Pick the frame by flow and port size.
- Choose the full impeller or the trim whose head is at or just above your figure.
Every trim is listed in the selection table.
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