ENGINEERING HUB · WATER SYSTEMS
The right valve.
The right coefficient.
Calculate flow from a published measurement coefficient and differential pressure. Match the full model, generation and test points before using a reading.
Using IMI HyTools? Select the same exact valve version in HyTools and here. STAD PN25 is identified as STAD* in IMI’s documentation. A similar name or DN does not establish the same calibration. This website uses the cited published data and has not been cross-validated against every HyTools app version.
01 / IDENTIFY
Select an exact reference
02 / CALCULATE
Differential pressure to flow
Load an exact valve reference to see its published settings, or choose manual entry if you have a verified manufacturer coefficient.
MEASUREMENT BASIS
Signal coefficient and valve resistance can differ.
Danfoss MSV-BD and Crane fixed-orifice devices have dedicated measuring arrangements. Use the measurement coefficient and the correct test plugs, not an unrelated full-valve resistance coefficient. A PICV or pressure-independent control valve must follow its own commissioning method.
The water reference equation is q = (Kv / 36) × √(ΔpkPa / SG) in L/s, equivalent to q = Kv × √(Δpbar / SG) in m³/h. Full-open Kvs does not describe a modulating valve at partial stroke.
ON-SITE CHECKS
Verify the measurement conditions.
- Check the nameplate, product generation, flow direction, pressure ports and valve position.
- Zero the instrument and remove trapped air from hoses using the manufacturer’s method.
- Allow stable flow, record fluid temperature and use the manufacturer’s fluid compensation.
- Respect valve/actuator limits; this calculator’s 1000 kPa input ceiling is not a pressure rating.
- Record the instrument, uncertainty, coefficient source and acceptance criterion with the result.
Read the commissioning handbook ↗
Employee timesheets ↗
