KROHNE OPTISWIRL 4070 EN - Manual (Page 14)

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DEVICE DESCRIPTION
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OPTISWIRL 4070
www.krohne.com 02/2013 - 4000150606 MA OPTISWIRL4070C R07 en
2.2.5 Device description
2.2.6 Free air delivery measurement - FAD (optional)
A (air) compressor draws air from the ambient atmosphere, compresses it and delivers it at the
required pressure. Since the ambient atmosphere also contains water vapour, what the
compressor draws in is a mixture of air and water vapour. Free air delivery measurement is to
be understood under this condition. Most manufacturers specify free air delivery only at
standard intake conditions. What the user ultimately requires as process air must first be
determined before measuring can take place with an accuracy of ±1%.
The vortex flowmeter with the optional FAD function can measure the free air delivery online,
humidity and speed compensated, regardless of its function as standard flowmeter. The
integrated software evaluates the free air delivery automatically online.
The menu-driven, user-friendly software prompts the operator to enter the pressure, relative
humidity, the required as well as current discharge pressure.
The steam tables and compressibility tables are saved as standard. The measuring device is
optionally available with a pressure sensor which measures the discharge pressure online,
making manual input of the values unnecessary.
Figure 2-4: Device description
1 Signal converter
2 Cable feedthrough grey, standard version
3 Pressure sensor, optional
4 Shut-off valve, optional
5 Measuring sensor
6 Centering ring
MA_OPTISWIRL4070C_R07_en_150606_PRT.book Page 14 Wednesday, February 13, 2013 2:47 PM