DH Instruments E-DWT-H, Руководство по эксплуатации и обслуживанию

Страница: 36 / 126

E-DWT-H OPERATION AND MAINTENANCE MANUAL
© 2009 DH Instruments, a Fluke Company Page 26
3.5.2 Pressure Generation And Rough Adjustment,
Variable Volume
W
Caution
The variable volume can generate very high pressure very quickly. When
using the variable volume, use caution not to generate pressure more
quickly than desired and not to exceed the pressure rating of the E-DWT-H,
it’s Q-RPTs or any component of the test system to which it is connected.
The variable volume is used to accomplish large pressure changes and to roughly adjust
pressure at a set point. It can generate high pressure with relatively little effort.
The variable volume is not designed to fill and prime the test system. To avoid needing to
refill the variable volume to reach the desired pressure, use the reservoir priming pump to fill
and prime the test system before going to the variable volume (see Section 3.5.1).
To generate and adjust pressure with the variable volume, proceed as follows:
Figure 11 and Figure 12 for a dual Q-RPT or Figure 1 and Figure 8 for a single Q-RPT
E-DWT-H schematic and view when following this procedure.
Open the reservoir shut off valve to connect the reservoir to the variable volume.
Close the TEST shut off valve to avoid ‘pulling’ oil out of the test system in step .
Rotate the variable volume CCW until the piston position indicator is at the beginning of
its stroke (indicator white).
Close the reservoir shut off valve to shut off the reservoir from the variable volume.
Open the TEST shut off valve to connect the variable volume to the test system.
If the E-DWT-H is dual Q-RPTs, check that the RPM4-E-DWT Q-RPT selection and Lo
Q-RPT shut off valve setting are correct for the pressure range.
While carefully watching the pressure indicated on the RPM4-E-DWT, rotate the variable
volume CW to increase pressure to the desired set point. Using the variable volume, it
should be easy to adjust the set pressure within 100 psi (700 kPa). To adjust pressure
more finely than is possible with the variable volume, use the fine adjust valve (see
Section 3.5.3).
If the variable volume runs out of stroke (piston position indicator red and variable volume
will not rotate CW further) before the desired set pressure is reached, the variable volume
can be isolated from the TEST port and refilled to continue generating pressure (see ).
To refill variable volume while the test system is under pressure proceed as follows:
Close the TEST shut off valve.
Record the pressure indicated by the RPM4-E-DWT. You will need to reset this
pressure to minimize the change in test pressure when you reconnect the refilled
variable volume to the test system
Slowly open the reservoir shut off valve.
Rotate the variable volume CCW to the beginning of its stroke (position indicator
white, variable volume will no longer rotate).
Close the reservoir shut off valve.
Rotate the variable volume CW to generate pressure until the pressure reaches the
value recorded in step . Use only the variable volume to adjust the pressure.
Slowly open the TEST shut off valve to reconnect the variable volume to the test
system. Continue to generate pressure as in .
To reduce pressure, rotate the variable volume CCW.