Applications
Steam/heat differential
(Steam production)
Application areas
Calculation of the heat quantity (energy) used to produce steam, as well as the calculation of the
steam mass flow and the heat quantity it contains. The heat energy contained in the feed water is
taken into account.
Measurements
Measurement of: operating volume and temperature in the feed water, as well as the
measurement of pressure and temperature directly after a steam producer.
Inputs
• Feed water circuit: Flow (q), temperature (T
W
)
• Steam network: Superheated steam: Temperature (T
D
) pressure (p)
Saturated steam: Temperature (T
D
)
Note!
Flow measurement can also be done in the steam pipes. In this case the operating mode “heating” must be
selected.
Calculated values
• Calculation of: mass flow, heat differential (steam heat content minus feed water heat
content), density, differential Enthalpy (IAPWS–IF97 Standard).
•
Only 2 inputs are required for saturated steam calculations (flow, pressure/temperature), the
missing input is calculated using the internally memorised saturated steam curves.
Note!
For higher accuracy or for control purposes, it is recommended to calculate the steam condition using 3 inputs
(super heated steam). This is recommended because in this operating mode the wet steam alarm function (see
outputs) can be used.
Output values /display at unit
• Heat flow, mass flow, flow (operating volume), temperature 1, temperature 2, pressure,
density, differential Enthalpy.
• Heat quantity sum, mass sum, flow sum.
Outputs
• All output values can be transmitted using the output terminals, this means both unchanged
inputs as well as calculated values. Please note that the number of outputs available is
dependent on the unit type.
• If a relay is set up for the “wet steam alarm”, this will operate as soon as the super-heated
steam reaches 2% of the saturated steam curve. An alarm message also appears in the display.
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