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SECTION 26 (Continued)
13. Make slow, complete strokes using the hand pump while pulling the hydraulic force
direction lever rearward. Quick, short strokes can negatively influence test results
and possibly damage the pump.
14. Once the PRV opens, release the hydraulic force direction lever to release the
hydraulic pressure being applied (See Notes Below).
15. Activate the spacebar to stop the measuring process.
NOTE
:
HYDRAULIC CLOSURE OF PRV:
The EVT PRO 2.0
®
can be used to
hydraulically close the PRV in the event the PRV hangs open. This is done by
pushing the hydraulic force direction lever forward to apply downward pressure on
the PRV spindle. In the event force-closing capability may be necessary, it is
imperative that the technician ensure the hardware bracket is securely mounted to
the PRV. GE/Consolidated recommends securing the mounting bracket underneath
the compression screw locknut to prevent the hardware bracket from pulling off the
PRV when downward pressure is applied.
NOTE
:
FLOW RESTRICTION
: The EVT PRO 2.0
®
Hand pump is designed to open
the PRV using a limited amount of pumping strokes. In order to generate a smooth
force line, hydraulic fluid is pumped through a restriction inside the pump. If it
becomes necessary to move the hydraulic cylinder quickly, the restriction can be by-
passed by closing the Black Knob (flow restriction device) located on the interface
panel. (Refer to figure 12.1)
During normal operation, this check valve should
remain open.
(FOR THE FOLLOWING REFER TO FIGURE 26.1)
16. Once the measuring process has been stopped, the test graph is ready for
evaluation
17. If a change in inlet pressure occurred before the valve was tested, or if the wrong
inlet pressure value was entered, activate the Correct Line Pressure action button
and enter the correct inlet pressure.
NOTE: To magnify a section of the test graph, click on the Zoom action button, which is
the button with the magnifying glass and highlight an area of the test graph to zoom.
18. Activate the Set pressure action button to display the green vertical line and use the
mouse to position the line at the point where set point was measured as indicated on
the graph. Refer to the section on Explanation of Graph for interpretation. In the
event the green vertical line is positioned incorrectly, reactivate the Set Pressure
action but to enable repositioning the line.
19. Activate the Reseat Pressure action button to display a second vertical line to
indicate reseat pressure
. It is important to understand that this is
only an indication
of reseat pressure
and that actual reseat pressure may be different.
20.
Conduct a minimum of 3 tests to verify set point repeatability
. Click on the
Complete Certificate action button to view and print the test certificate.
EVT PRO 2.0
®
PERFORMING A TEST
EVT PRO 2.0
®
Operations and Technical Manual (Rev 1.0
– 2016)
NOT FOR COPY OR DISTRIBUTION
Page 32
Содержание EVT-Pro 2.0
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