Steam Valve Capacity and Size Selection
To determine the valve capacity and select the correct valve size, you need to enter the required data into the green-colored fields in the calculation table below.
Steam valve sizing requires a different calculation method compared to hot water and cooling applications. The results obtained from the valve calculations are displayed in the red-colored sections of the table.
The most important value obtained from the calculation is the Kvs value. The valve brand or model to be used should be selected according to this data. A valve with a capacity lower than the calculated Kvs value should not be used.
Steam Valve Calculation Table
Only the green-colored fields in the calculation table below should be filled in. The result values will automatically be displayed in the red-colored fields.
Note: The results provided in the calculation table should be used for preliminary selection purposes only. When making the final valve selection, manufacturer catalog values, operating pressure, temperature, connection type, and application conditions should also be checked.
Proper Valve Selection for Steam Applications
Valve selection in steam systems requires more careful evaluation compared to liquid fluids. Steam pressure, temperature, flow rate, and operating conditions directly affect valve capacity.
For this reason, steam valves should not be selected solely based on pipe diameter. The Kvs value of the valve body must be capable of meeting the steam flow rate and should be selected according to the operating conditions of the system.
- Steam pressure and temperature must be determined accurately.
- A valve with a capacity lower than the calculated Kvs value should not be selected.
- The valve body, actuator, and connection type must be suitable for the application.
- Depending on the required control accuracy, On/Off, 3-point, or proportional control should be preferred.
The Importance of the Kvs Value
The Kvs value is the main capacity value used in valve selection. If a valve with the correct Kvs value is not selected in steam applications, control accuracy may decrease, the valve may not operate at full capacity, or fluctuations may occur in temperature control.
If the valve capacity is selected smaller than required, the system may not be able to provide the desired flow rate. If the valve is selected too large, control may become difficult at low opening rates. Therefore, the valve model with the closest suitable higher capacity to the calculated Kvs value should be preferred.
When selecting a steam valve, the calculation result must be checked together with the maximum operating pressure, temperature resistance, connection standard, and actuator closing force.
In summary, the most important criterion in steam valve selection is accurate capacity calculation. The Kvs value obtained as a result of the calculation should be used as the basis for valve body selection, while the application's pressure, temperature, connection, and control accuracy requirements should also be evaluated.