Molbloc-S Pressure Dependent Calibration Types; Table 6. Molbloc-S Calibration Types - Fluke MOLBOX RFM Operation And Maintenance Manual

1.2.4.2.2 molbloc-S PRESSURE DEPENDENT CALIBRATION
TYPES
See your molbloc's Calibration Report to determine the calibration type of
the molbloc you are using.
Measurement uncertainty (accuracy) specifications for molblocs are valid only for
gases with which the molbloc has been calibrated. All molbloc-S elements are
calibrated in one standard gas, either air or N2, and may be calibrated in other
gases. Calibrations with other gases are optional. The set of gases which can
be measured by molbloc-S is separate from the list of molbloc-L gases, and may
be more limited. DHI calibration capability is not maintained at all times for all
gases on all molbloc sizes. Check for availability before ordering calibrations.
molbloc-S calibrations are performed over flow ranges corresponding to one of
two pressure ranges, summarized in Table 6.

Table 6. molbloc-S Calibration Types

CALIBRATION TYPE
LP
low pressure
SP
standard pressure
molbloc-S flow measurements are valid only when the ratio of pressure
downstream to pressure upstream of the nozzle is high enough to assure a
critical (choked) flow (see Section 3.1.2).
OPERATING PRESSURE
20 to 200 kPa absolute (3 to
30 psia
upstream of molbloc
50 to 500 kPa absolute (7 to
70 psia)
upstream of molbloc
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