Aalborg GFM - Manual (Page 15)

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6.2.2 GFM 17 models
Unscrew the inlet compression fitting of meter. Note that the Restrictor Flow
Element (RFE) is connected to the inlet fitting.
Carefully disassemble the RFE from the inlet connection. The 50 micron filter
screen will now become visible. Push the screen out through the inlet fitting. Clean
or replace each of the removed parts as necessary. If alcohol is used for clean-
ing, allow time for drying.
Inspect the flow path inside the transducer for any visible signs of contaminant. If
necessary, flush the flow path through with alcohol. Thoroughly dry the flow paths
by flowing clean dry gas through.
Carefully re-install the RFE and inlet fitting, avoiding any twisting and deforming
the RFE. Be sure that no dust has collected on the O-ring seal.
NOTE: OVER TIGHTENING WILL DEFORM AND RENDER THE RFE DEFECTIVE.
it is advisable that at least one calibration point be checked after re-installing the
inlet fitting-see section (7).
7. CALIBRATION PROCEDURES
NOTE: REMOVAL OF THE FACTORY INSTALLED CALIBRATION SEALS AND/OR
ANY ADJUSTMENTS MADE TO THE METER, AS DESCRIBED IN THIS SECTION,
WILL VOID ANY CALIBRATION WARRANTY APPLICABLE.
7.1 Flow Calibration
Aalborg
7 Instruments' Flow Calibration Laboratory offers professional calibration
support for Mass Flow Meters, using precision calibrators under strictly controlled
conditions. NIST traceable calibrations are available. Calibrations can also be per-
formed at customers' site using available standards.
Factory calibrations are performed using NIST traceable precision volumetric
calibrators incorporating liquid sealed frictionless actuators. Generally, calibra-
tions are performed using dry nitrogen gas.
,
,
IT IS NOT RECOMMENDED TO ATTEMPT TO DISASSEMBLE, OR REPAIR
GFM37, GFM47, GFM57, GFM67 AND GFM77 MODELS. DISASSEMBLY
NECESSITATES RE-CALIBRATION.
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