As outlined in chapter "2.8.3 Impact of fluid properties on valve sizing", page 36, when sizing a valve, the density ρ, the specific heat capacity c, and the kinematic viscosity ν must be taken into consideration. Also, to ensure correct and efficient operation, a closer look should be taken at the controlled mode and the startup mode.
Properties |
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|---|---|
Description |
Mobiltherm 603 |
Max. permissible flow temperature |
285 °C |
Max. permissible film temperature |
315 °C |
Kinematic viscosity at 20 °C |
50.5 mm2/s |
Kinematic viscosity at 100/200/300 °C |
4.2/1.2/0.58 mm2/s |
Density at 20 °C |
859 kg/m3 |
Density at 100/200/300 °C |
811/750/690 kg/m3 |
Specific heat capacity c at 20 °C |
1.89 kJ/kgK |
Specific heat capacity c at 100/200/300 °C |
2.18/2.54/2.91 kJ/kgK |
When planning and commissioning a plant or when sizing valves, the suppliers’ specifications must be observed. The experience and know-how of the suppliers help select the right type of heat transfer oil.
Plant data |
Consumer: Air-heat transfer oil heat exchanger Differential pressure ∆pVR: 50 kPa (0.5 bar) Flow temperature TVL: 280 °C Return temperature TRL: 230 °C Required capacity Q100: 55 kW Basic hydraulic circuit: Throttling circuit |
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|---|---|---|
Operating data |
Controlled mode when heated up |
Heating up mode |
Required capacity Q |
Q100 = 55 kW | Q is undefined |
Temperature spread ΔT |
50 K | - |
Determine the volumetric flow V100 |
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- |
Differential pressure ΔpV100 |
With pressure and variable volumetric flow 🡪 🡪 ΔpV100 = 25 kPa (0.25 bar) |
Must be calculated |
Flow temperature TVL |
280 °C |
Approx. 20 °C |
Kinematic viscosity ν |
At 300 °C: 0.58 mm2/s |
50.5 mm2/s |
Correction factor FR |
At 280 °C: 1 Kinematic viscosity υ <10 mm2/s |
At 20 °C: 0.75 Interpolated according to the correction factor table on page 39 |
Determine the kvs value |
FR = 1
kvs value ≥ 0.85 • 3.94 m3/h = 3.35 m3/h -> kVS value = 5 m3/h |
- |
Volumetric flow resulting from the selected kvs value |
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🡪 In the heating up phase, the volumetric flow is reduced by 5 %! |
Select the 2-port valve |
VVF61.242 |
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