Yokogawa digitalYEWFLO (DY) - Manual (Page 110)

GLOSSARY OF TERMS
IM 1F2B4-01-YIA
Page 105
Mass - The weight of a fluid normally expressed in pounds or kilograms. Mass flow is the flow rate
expressed in weight units per unit time such as pounds per hour.
N balance - Noise Balance a Parameter used to reduce the effects of vibration or pipe noise which
may cause the meter to have an output when there is no flow. Adjusting this parameter will not affect
the meter accuracy or K-factor.
L. C. flow rate - The parameter (H07) sets a flow rate below which the flowmeter output will always
be zero. This is normally set at the factory at 90% of the nominal minimum measurable flow.
Normal conditions - A term frequently found when the operating conditions are given in metric units.
The temperature is 0°C and 14.7 PSIA as opposed to the English Standard conditions of 60°F and
14.7 PSIA. Note: Standard Conditions are used most frequently in North America.
Operating conditions - The fluid properties of specific gravity, viscosity, density, temperature and
pressure at which the flowmeter will be expected to perform its meter function.
Parameter - A portion of the configuration of the YEWFLO where information is entered and/or read
using either the BT100/BT200 or TBL.
Piezoelectric crystals - the sensor used in the YEWFLO. When there is a change in the stress applied
to the piezoelectric crystal, a momentary voltage spike is generated. The crystal is not sensitive to
static pressure or stress, it only reacts to changes in the stress.
Pipe effect - The YEWFLO is designed to operate installed in schedule (sch) 40 pipe. Other pipe
schedules such as sch 10 or sch 80 have different internal dimensions. This will mismatched pipe bore
can affect the meter factor (K-factor). This error can be corrected out by activating the Pipe Effect
parameter (D05) and selecting the correct combination of process connection and piped schedule.
Remote converter - Electronics for the YEWFLO which are located up to 65 feet away from the
vortex meter body.
Reynolds number - A dimensionless number taking into account the flowing velocity, fluid density and
viscosity and the pipe cross-sectional area. It provides a means to predict the flow profile of the fluid
within the pipe under flowing conditions.
Self-check - The YEWFLO electronics checks all phases of the meter’s performance any diagnostic
errors are displayed at any menu (Letter) with parameter value (number) of 60, i.e. A60, D60 etc.
Shedder bar - The bluff body or non-streamlined object located in the middle of the flow stream by
which vortex swirls are formed and detached or shed.
Span frequency - The frequency of vortex shedding that would be generated at 100% of span setting,
and would generate 20 mA output in the case of an analog output meter.
Span velocity - The velocity of the flow at the span setting (20 mA). Normally expressed in terms of
meters per second.
Standard cubic feet (SCF) - A volume equal to a cubic foot of gas when allowed to expand or
contract so that the pressure is 14.7 PSIA and 60ºF.