DH Instruments OPG1-30000-AF, Operation And Maintenance Manual, Page: 28 / 44

OPG1™ Operation and Maintenance Manual
©2000 DH Instruments, Inc .
Page 22
With the INLET valve (5) closed, use the DRIVE SET regulator (4) and the PUMP DRIVE
gauge (3) indication to set the desired maximum pump output pressure. This is generally
done at the beginning of a test or calibration based on the maximum pressure of
the calibration. It is good practice to set the pump output pressure below the maximum
pressure desired to avoid accidental overpressure. The PDVV can then be used for the final
pressure adjustment at the maximum pressure (see Section 3.2.3).
The DRIVE SET regulator sets the oil pressure output of the hydropneumatic pump. When the
INLET valve is opened, this pressure can be generated very rapidly in the system connected
to OPG1. Use caution in setting the pump drive pressure and always check the setting and
adjust if necessary before using the INLET valve (see Sections 2.4.2 and 3.2.1).
3.2.2 ROUGH PRESSURE GENERATION/CONTROL, INLET AND OUTLET
VALVE OPERATION
Numerical references in this section refer to Section 3.2, Figure 6.
The INLET valve (5) and OUTLET valve (8) are high pressure needle valves.
Their operation is highly progressive over a half-turn with mechanical stops at each end so
they cannot be overtightened. The valve is turned CW to close and CCW to open. A WHITE
dot on the handle body indicates its current open/close position.
The INLET valve (5) controls the flow of oil from the hydropneumatic pump into the
test system. When the INLET valve is closed, the pump is shut off from the test system and
dead ended. When the INLET valve is open, the pump output is connected to the test
system and can fill and generate pressure into the system.
The OUTLET valve (8) controls the flow of oil from the test system back to the tank. When it
is closed, the test system is shut off from the tank. When the OUTLET valve is open, the
system returns oil to the tank and is opened to atmospheric pressure.
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 connect to the
pump to purge and prime the test system at the beginning of a test or calibration.
The
OUTLET valve , when fully opened, is the means of opening the test to atmosphere and
setting zero pressure. The INLET valve and OUTLET valve are not generally used for
ON/OFF action but progressively to roughly set the desired pressure. Exercise caution when
operating the valves to not open them too quickly which may cause pressure in the system to
change much more rapidly than desired.
The INLET valve connects the output of the hydropneumatic pump to the test system.
When the INLET valve is opened, high pressure can be generated very rapidly in the system
connected to OPG1. Use caution in opening the INLET valve and always check the PUMP DRIVE
gauge before doing so (see Sections 2.4.2 and 3.2.1).