Badger Meter Vortex Meters - Manual (Page 25)

Page 23
The main purpose of this window is to allow the user to specify the source that the meter
should use for density and viscosity information. This information is required by the meter in
order to accurately calculate flow.
There are three sources for density and viscosity information; a property table, user defined
density and viscosity values, and the steam property table.
Note that the ‘Steam Table’ selection here is not referring to a saturated steam table, but a steam property
table that contains density and viscosity information for saturated and superheated steam.
property Table - This selection causes the meter to use the property table as the source of
process density and viscosity information. Property tables provide accurate density and viscos-
ity information over a wide range of process temperatures and pressures. Property tables are
loaded into the meter using the “Property Table” dialog box accessible from the “Tools” menu.
The user can ensure that the appropriate property table is loaded by verifying the property
table name is in the “Property Table Name” field. Using a property table allows the meter to ac-
curately calculate flow over a wide range of temperature and pressure.
User Defined -This selection causes the meter to use constant density and viscosity values. If
this source is selected, the density and viscosity values entered in the “User Defined Density”
and “User Defined Viscosity” fields are used. When constant density and viscosity values are
used, the meter cannot compensate for changes in temperature or pressure.
steam Table - This selection causes the meter to use a steam property table as the source for
density and viscosity information. This property table provides accurate density and viscosity
information over a wide range of process temperatures and pressures for saturated and su-
perheated steam. The steam property table allows the meter to accurately calculate flow over
a wide range of temperature and pressure. This table is always resident in the meter and does
not need to be loaded.
User Defined Density - This field allows the user to enter a constant process density value.
This value is only used when “User Defined” is selected as the density and viscosity source.
The unit for this field is lb/CuFt.
User Defined Viscosity - This field allows the user to enter a constant process viscosity value.
This value is only used when “User Defined” is selected as the density and viscosity source.
The unit for this field is Centipoise (cP).
property Table name - This field displays the property table name that has been loaded into
the meter. The steam property table is always resident in the meter and need not be loaded.
Therefore, it is typical for a steam meter to have the AIR property table loaded, but be config-
ured to use the memory resident steam property table as the source for density and viscosity
information. For non-steam applications, when “Property Table” is selected as the source for
density and viscosity information, make sure that the property table name agrees with what is
actually being metered.