DH Instruments OPG1-30000-AF, Руководство по эксплуатации и обслуживанию, Страница: 31 / 44

OPG1™ Operation and Maintenance Manual
Page 25
©2000 DH Instruments, Inc .
3.2.6 MEASUREMENT REFERENCE LEVEL WHEN VENTED
Generally, the test or calibration system is opened to atmosphere (zero gauge pressure) by
opening the OPG1
OUTLET valve .
The fluid head reference level when the OUTLET valve is open is the top of the tank return
overflow tube. This point is 258 mm (10.15 in.) above the surface on which OPG1 is sitting
(see Figure 8).
Figure 8. Fluid Head Level When Vented, INLET Valve Open
When the OUTLET valve is closed, the fluid head reference level is at the device being used
as the measurement reference. Consider the possible difference in fluid head between the
two conditions or incorrect fluid head corrections will be applied and the zero point will be
inconsistent with other measurements.
See the RPM3/HPMS-A30000/A6000-AF Operation and Maintenance Manual for
recommendations on setting zero and handling fluid heads when using OPG1 in an
HGC-30000-AF system.
OPG1 is designed so that the top of the oil tank return overflow tube aligns with the
measurement reference level of a PG7302 oil operated piston gauge. This assures that, when
using a PG7302 piston gauge, the nominal reference level is the same at zero with the OPG1
vented and when pressures are defined by the piston gauge.
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When the OPG1 OUTLET valve is open, the test system is connected to the OPG1 oil tank.
If there is an open point in the test system below the oil level in the oil tank, oil will run from
the tank and out of the open point in the test system.