How much steam passing valve.
Refers to how great the pressure before and after the valve is.
Specific volume can also be called volume defined as the volume per mass, ie the volume of a certain amount of mass of steam.
The specific volume (v1) only applicable to non-critical flow while the specific volume (v2) is for critical flow.
Kv = Water flow in m 3 /h at a pressure drop over open valve of 1 bar (100 kPa).
Kvs = The Kv value of the selected valve at fully open valve. Usually with a 30% safety margin to the calculated Kv value.
Difference between Kv and Kvs
Kvs value is the value of the component and Kv-value is the value that the component is expected to have at the operation case.
The CV value is the American equivalent of the KV value. The CV value is defined as the water flow in the US gallon over a fully open valve with a pressure of 1 psi.
| KV-value subcritical steam: |  |
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|---|---|---|
| KV-value supercritical steam: |  |
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| CV-värde: |  |