# Calculation Programs

We have compiled some calculation options for you. For liquids and gases it is possible to calculate the kv value, the flow Q and the pressure drop p. With the calculations for gases, one additionally distinguishes between the under-critical (p2 > p1/2) and over-critical cases (p2 < p1/2).

All calculations are purely practical formulas, i.e. simplifications for the respective case, which may only be used with the specified units.

### Calculations for liquids

#### kv value

In order to calculate the kv value the flow Q, the density ρ1 of the media at the valve inlet and the pressure drop (Δp) across the valve must be known:

 Q = m³/h = m³/h ρ1 = kg/m³ Δp = bar

#### Flow

In order to calculate the flow Q the kvvalue, the density ρ1 of the media at the valve inlet and the pressure drop (Δp) across the valve must be known:

 kv = m³/h = m³/h ρ1 = kg/m³ Δp = bar

#### Pressure Drop

In order to measure the pressure drop Δp the kv value, the density ρ1 of the media at the valve inlet and the flow Q must be known:

 kv = m³/h = bar ρ1 = kg/m³ Q = m³/h

### Calculations for Gases

#### kv value

In order to calculate the kv value the volumetric flow QN at 1013 hPa and 0°C, the standard density ρN of the media, the pressure drop (Δp) across the valve, the media pressure p2 downstream of the valve and the media temperature at the valve inlet must be known:

Qn = Nm³/h = m³/h
ρn = kg/Nm³
Δp = bar
p2 = bar = m³/h
T1 =
 °C °F

#### Flow

In order to calculate the flow QN the kv value, the standard density ρN of the media, the pressure drop (Δp) across the valve, the media pressure p2 downstream of the valve and the media temperature at the valve inlet must be known:

kv = m³/h = Nm³/h
ρn = kg/Nm³
Δp = bar
p2 = bar = Nm³/h
T1 =
 °C °F

#### Pressure Drop

In order to calculate the pressure drop Δp the kv value, the volumetric flow QN at 1013 hPa and 0°C, the standard density ρN of the media, the media pressure p2 downstream of the valve and the media temperature at the valve inlet must be known:

kv = m³/h = bar
Qn = Nm³/h
ρn = kg/Nm³
p2 = bar     if
T1 =
 °C °F

### Flow Q for liquids in l/min

 DNinmm Flow Velocity 0,5m/s 1,0m/s 1,5m/s 2,0m/s 3,0m/s 4,0m/s 5,0m/s 7,0m/s 8,0m/s 10,0m/s 8 1.5 3.0 4.5 6.0 9.0 12.1 15.1 21.1 24.1 30.2 10 2.4 4.7 7.1 9.4 14.1 18.8 23.6 33.0 37.7 47.1 12 3.4 6.8 10.2 13.6 20.4 27.1 33.9 47.5 54.3 67.9 15 5.3 10.6 15.9 21.2 31.8 42.4 53.0 74.2 84.8 106.0 16 6.0 12.1 18.1 24.1 36.2 48.3 60.3 84.4 96.5 120.6 20 9.4 18.8 28.3 37.7 56.5 75.4 94.2 131.9 150.8 188.5 25 14.7 29.5 44.2 58.9 88.4 117.8 147.3 206.2 235.6 294.5 32 24.1 48.3 72.4 96.5 144.8 193.0 241.3 337.8 386.0 482.5 40 37.7 75.4 113.1 150.8 226.2 301.6 377.0 527.8 603.2 754.0 50 58.9 117.8 176.7 235.6 353.4 471.2 589.0 824.7 942.5 1178.1 65 99.5 199.1 298.6 398.2 597.3 796.4 995.5 1393.7 1592.8 1991.0 80 150.8 301.6 452.4 603.2 904.8 1206.4 1508.0 2111.2 2412.7 3015.9 100 235.6 471.2 706.9 942.5 1413.7 1885.0 2356.2 3298.7 3769.9 4712.4 125 368.2 736.3 1104.5 1472.6 2208.9 2945.2 3681.6 5154.2 5890.5 7363.1 150 530.1 1060.3 1590.4 2120.6 3180.9 4241.2 5301.4 7422.0 8482.3 10602.9 200 942.5 1885.0 2827.4 3769.9 5654.9 7539.8 9424.8 13194.7 15079.6 18849.6 250 1472.6 2945.2 4417.9 5890.5 8835.7 11781.0 14726.2 20616.7 23561.9 29452.4

To avoid hydraulic shocks in pipelines, the flow velocities must be taken into account when designing valves for liquids.