Fluke RUSKA 7252, User Manual

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Maintenance
Calibration
6
6-7
Vacuum (Negative Gauge) Calibrations
Vacuum mode is an available option. The following configuration should be used when
calibrating in the Vacuum mode.
METERING
VALVE
TEST
REFERENCE
DPC
PRESSURE
CONTROLLER
EXHAUST
DEADWEIGH GAUGE
INLET
REF VACUUM
SYSTEM
PRESSURE & VACUUM
glb11.eps
Figure 6-3. Vacuum (Negative Gauge) Calibration
To calibrate in Vacuum mode with the configuration shown in Figure 6-3, the following
actions should be taken.
1.
The system pressure and vacuum inlet valve should remain closed.
2. The bottom side of the piston must be open (vented) to atmosphere and connected to
the reference port of the DUT.
3. The test port of the DUT must be connected to the bell jar with a cutoff valve to
isolate it from the DUT.
4. Additionally, there must be a cutoff valve located between the Vacuum pump and the
bell jar.
5. Close the Cut-off valve to isolate the DUT test port from the bell jar.
6. Open the Vacuum Pump Valve to pull a hard vacuum on the bell jar to seal the bell
jar and to float the masses.
7. Once the masses have risen in response to evacuation of the bell jar, close the
reference vacuum pump cutoff valve.
8. Use the metering valve on the bell jar to adjust (vent) the bell jar vacuum towards
atmosphere until the masses begin to float. Close the metering valve as soon as the
masses begin to float.
9. Open the bell jar cutoff valve to the test port of the DUT, close the exhaust (Vent)
valve, and use the pressure adjuster handwheel to adjust float position of the
deadweight gauge to float the piston at mid- float position.