Thermo Scientific Sarasota FD900, User Manual

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Thermo Fisher Scientific User Guide for Sarasota ID900, FD900, & PD900 Gas Density Meters
3-7
Commissioning
Setting the Bypass
Flow Rate
Sarasota PD900
In normal applications there is usually too much differential pressure
available to drive flow around the bypass. Therefore, bypass flow must be
regulated at the valve which does not lie between the meter and the selected
density measurement point.
A suitable flow rate may be set up as follows:
1. With normal flow in the main line, open both valves fully to allow fast
temperature stabilization of the system. The temperature at the density
measuring spool may be displayed on the Sarasota HME900 or
CM515.
2. Close the valve on the opposite side of the bypass to the density
measuring point. The density reading then displayed by the computer
is the density at the chosen point and will be very accurate since there
are no pressure errors and temperature isstable.
3. Re-open the valve very slowly and observe the density reading. It will
change as flow through the bypass causes a change in pressure. A small
change is acceptable, commensurate with the system accuracy required.