Omega FD6003 - Manual (Page 7)

1-5
The flowmeter is typically used as a unidirectional
meter and is most accurate when the transducer is
mounted in the orientation detailed in this manual.
But, the meter will measure flow in both directions —
although flow direction will not be indicated or
totalized properly. The flowmeter will operate from
signals returned from turbulence alone (such as
installation directly at pump discharges or
downstream from elbows and valves); however, it
should be noted that turbulence may vary with flow
rates and result in non-linear results. The
repeatability of the device is not dependent on most
process liquids.
The flowmeter is designed to measure the flow of
liquids and slurries, as long as a small, homogeneous
quantity of entrained air or suspended solids are
present. Without the presence of continuing supply of
air or solids, the transmitted pulses are not reflected
back to the transducer and the indicator will indicate
zero flow.
The signal strength value will indicate a value greater
than 100 counts when a minimum size and
concentration of suspended particles are available for
a reliable flow reading (100 micron and 100 PPM
minimum) and the liquid is moving at least 0.1 FPS
[0.03 MPS]. Most water-based liquids can be
measured from a factory calibrated flowmeter.
However, liquids with a heavy solids level (i.e. over
2% by volume), liquids with sound speeds that vary
from water (see Appendix - Liquid Sound Speed list)
or pipes with liners may have to be field calibrated.
This is done by adjusting the Calibration value on the
keypad to make the indicator agree with a known flow
velocity or a mathematically corrected fluid velocity.
All standard flow meters are calibrated to measure
the flow of a water-based liquid at 25 degrees C. If
the scale range or units need to changed, the process
to do so is covered in detail later in this manual.
PART 1 - GENERAL
Measuring Limits