DH Instruments FPG8601, Руководство по эксплуатации и обслуживанию

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FPG8601™/VLPC™ OPERATION AND MAINTENANCE MANUAL
© 2007 DH Instruments, a Fluke Company Page 118
Cap the VLPC connection ports on the FPG manifold. The VLPC is not used in the cross float.
It must be isolated to simplify the flow adjustments with the metering valve.
Using several lengths of 1/4 in. PFA tubing, connect the following together.
•
Test outlet on the pressure controller.
•
Test on the back of the PG (and CCP port if Model PG7000).
•
The valve that is on the upper left port of the FPG. Use a 1/4 in. SWG X KF16
adapter for connecting to this port.
When using a PG7000, make sure that the vacuum connection on the back of the unit is
open to atmosphere.
7.8.2 GENERATING A PRESSURE
Load the required mass on the piston gauge to set the test pressure.
•
When using a
DHI
PG7000, use only 1.0 kg masses and place the bell jar over the
total mass load. The bell jar prevents atmospheric disturbances from affecting the
test pressure. The 1.0kg masses have a smaller diameter and limit the parasitic
forces caused by air currents generated in the bell jar.
\
Always limit atmospheric disturbances during the cross float. Opening and
closing doors will affect the test. This is especially true when a bell jar is not
placed over the piston gauge mass load.
Determine the actual piston gauge pressure as recommended by the manufacturer.
When using a PG7000, make sure that the mass set, mass bell and piston-cylinder are
selected in the PG Terminal. Then enter the mass load in the terminal to get the fully
compensated pressure. If FPG Tools is using the PG7000 remotely,
Open the isolation valve between the FPG and the PG.
Close the FPG bypass valve (valve 10) and open the vacuum isolation valve (valve 9) on
the FPG.
Open the control isolation valve (valve 11).
Generate a pressure using the pressure controller, floating the piston of the PG.
Once the pressure is achieved, close the isolation valve between the FPG and PG.
The FPG pressure and piston gauge pressure should be approximately equal at this point.
With the isolation valve closed, the piston gauge should continue to float at the target
pressure provided there are no leaks in the system.
7.8.3 ADJUSTING THE NEEDLE VALVE
Adjust the needle valve to cause the rate of change of the FPG pressure, as read by FPG
Tools, to oscillate around 0.00mPa/sec. If desired, use strip chart feature in FPG Tools
by double clicking the FPG pressure rate on the
<Run Display>
. When the valve is
adjusted properly, the pressure rate should be evenly distributed about horizontal plot
axis (Y=0).
•
Turn the needle valve clockwise in order to increase the rate of change in pressure
and counter clockwise to decrease the rate of change in pressure.
Open the isolation valve between the FPG and piston gauge.
Re-adjust the pressure controller to float the piston gauge piston, as required.
Verify that opening and closing the isolation valve does not effect the piston gauge drop
rate. If the isolation valve state affects the drop rate of the piston gauge piston, the
needle valve must be readjusted. In this case, repeat step 1.