FPG8601™/VLPC™ OPERATION AND MAINTENANCE MANUAL
© 2007 DH Instruments, a Fluke Company
Page 122
Figure 64.
FPG8601 Bubbling System
In
Figure 64, the coalescing filter is on the left and the bubbler is on the right. This view is looking at
the back of the FPG8601.
Drain the coalescing filter by placing a lint-free towel under the filter, then pressing the button on the
bottom of the filter.
Remove the bubbler by turning the plastic volume counter-clockwise.
Fill the bubbler to about 30 % of its capacity with clean distilled water.
Tighten the bubbler 1/4 turn clockwise after it feels snug against the O-ring.
Verify that the FPG is level.
Using FPG Tools, select gauge mode to resume normal operation or press the
[Restart FPG]
icon on
the functions toolbar.
8.3
ZEROING THE VACUUM SENSOR
The vacuum reference sensor is used in absolute mode for measuring the reference pressure on the low
pressure port of the FPG. This critical device must be re-zeroed at consistent intervals to maintain
accuracy in absolute mode. This process describes warm up time, set-up, and testing the zero of the sensor.
FPG Tools should be used during this process to view the output of the sensor.
This section describes specific detail related to a Varian Turbo Pump model V70LP. However, any turbo
pump capable of achieving a vacuum significantly less 0.001 Pa will work.
The position of the vacuum reference sensor when zeroed should be used in normal operation. Changing the
position can have a significant effect on the sensors zero. It is recommended that the sensor be zeroed in
the vertical orientation. When zeroed horizontally, the rotation of the sensor also affects the zero. This
makes it difficult to mount, remove and remount the sensor without affecting the zero.
Table 44.
Vacuum Reference Zeroing Equipment List
EQUIPMENT
FPG
FPG Tools Software
Various KF fittings
Varian turbo pump model V70LP and controller
or equivalent
Roughing pump
(Optional) Ion Gauge
