GPC1-10000 / GPC1-16000
™
OPERATION AND MAINTENANCE MANUAL
© 2007 DH Instruments, a Fluke Company
Page 20
3.2.2
ROUGH PRESSURE GENERATION/CONTROL, INLET
AND OUTLET VALVE OPERATION
Numerical references in this section refer to Section 3.2, Figure 7. For information on the
GPC1 operating principle, see Section 3.1.
The
INLET valve
(5) and
OUTLET valve
(8) are used to execute large pressure changes in the
test system and for rough pressure control. The
INLET valve
is used to increase pressure and
the
OUTLET valve
, decreases pressure and vents the system to atmosphere, setting zero gauge
pressure. If finer pressure control, use the
PDVV valves
(see Section 3.2.3).
To increase pressure in the GPC1 system, open the
INLET valve
(5) slowly. Use the
progressive nature of the valve to control the rate of pressure increase. Close the valve
when the desired pressure has been reached. When a gas booster is used to supply high
pressure, the booster may not be able to keep up with the flow rate needed to set the desired
pressure. In this case, with the
INLET valve
open, wait for the booster to reach the desired
pressure.
To decrease pressure in the GPC1 system, open
OUTLET valve
(8) slowly. Open the valve
fully to vent the system to atmosphere (set zero gauge).
The TEST INLET valve connects the pressure supply to the test system. When the TEST
INLET valve is opened, high pressure can be generated rapidly in the system connected to
GPC1. Use caution in opening the TEST INLET valve and always check the TEST INLET
pressure gauge before doing so (see Section 2.4.2).
3.2.3
FINE PRESSURE ADJUSTMENT, PDVV (+) AND (-)
VALVE OPERATION
Numerical references in this section refer to Section 3.2, Figure 7 except where
specified otherwise. For information on the GPC1 operating principle, see Section 3.1.
Use the valves labeled
and
to release gas from the PDVV actuator, causing the PDVV
plunger to back off and pressure to decrease. Use the valves labeled
are
to admit gas
to the PDVV actuator, causing the PDVV plunger to move forward and pressure to increase.
The
and
valves are for high speed PDVV operation
.
The
and
valves are for slow speed
PDVV operation.
The
PDVV (+)
(6) and
(-) valves
(7) are utilized to make small pressure changes and for fine
pressure control. Brief momentary action on the
and
valves is used to
bump
or
jog
pressure in very small amounts around a pressure point.
If the PDVV plunger reaches end of stroke during a calibration or test, use the
INLET valve
(5)
and/or
OUTLET valve
(8) to increase or decrease the pressure, as needed (see Section 3.2.2).
The actual rate of pressure change caused by the
PDVV (+) valves
and
PDVV (-) valves
is
dependent on the test volume that is connected to GPC1 and the current pressure value.
Increasing the test volume lowers the pressure change rate and pressure step size.
Increasing the volume increases the rate and the pressure step size. The maximum
pressure that can be generated by the
PDVV (+) valves
is dependent on the PDVV drive air
supply (see Section 2.3.2, Table 2).
