A rated Cv table lists capacity for a particular valve construction and stated opening. It helps compare that product’s sizes, but it is not a complete selection chart for every fluid or operating case.
What the historical data shows
The supplied V-type operating manual and the historical VPORTA VQF catalogue include a rated-capacity table. Selected values are reproduced below as reference data. They belong to the documented configuration and must not be assumed for every current VQ47, VQ77, seat or reduced-capacity trim. Ask for the current curve attached to your offer.
Why a smaller required coefficient is not enough
If a process needs Cv 30, a valve rated far above that number might pass the flow at a small opening, but its useful control range could be poor. Compare the minimum, normal and maximum required coefficients with the full Cv-versus-travel curve. Check pressure recovery and media effects as well as full-open capacity.
Keep the values traceable
Record the catalogue series, revision and the manufacturer’s confirmation of the proposed trim. Do not interpolate a different series solely from nominal diameter. A useful quotation states the selected configuration, expected operating travel and any limitations on the calculation.
| Nominal size | Historical rated Cv |
|---|---|
| DN25 | 36 |
| DN50 | 152 |
| DN80 | 358 |
| DN100 | 540 |
| DN150 | 1424 |
| DN200 | 2176 |
| DN250 | 3532 |
Practical checklist
- Rated capacity is not an operating-point recommendation.
- Series and trim must match the reference.
- Use the full travel curve for control selection.
- Confirm the approved current datasheet.
Discuss your application
Send the process conditions and required valve function for a configuration review. Request a technical quotation ↗