Section II – Pressure System Requirements
MN06146 Issue/Rev. 0.1 (7/10)
3
For accurate measurement, adequate back pressure
at the meter is required to prevent cavitation. For a
turbine meter at its maximum rated flow, this will be
approximately 20 psi plus the vapor pressure of the
product being metered (e.g., about 15-20 psig for
gasoline). For a positive displacement meter, 5 psi
plus vapor pressure (e.g., about 0-5 psig for gaso-
line) is sufficient. Back pressure may be a problem
at the maximum flow rate if system pressure loss
downstream of the meter is quite low. This is most
likely to occur, particularly in a turbine meter system,
if the set stop valve goes to a wide open position
(i.e., is not controlling flow).
With a pressure gauge between the meter and
valve, adequate meter back pressure during proving
may be verified.
Summary of Contents for Smith Meter AccuLoad
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